Dodge Factory Cooling 2003 Service Manual

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DR COOLING 7 - 1

COOLING

TABLE OF CONTENTS

page page

COOLING

DESCRIPTION

DESCRIPTION - COOLING SYSTEM FLOW

3.7L/4.7L ENGINE ......................1

DESCRIPTION - COOLING SYSTEM FLOW -

5.9L ENGINE ..........................1

DESCRIPTION—COOLING SYSTEM FLOW -

5.9L DIESEL ..........................2

DESCRIPTION - HOSE CLAMPS ...........3

OPERATION

OPERATION—COOLING SYSTEM .........3

OPERATION—HOSE CLAMPS ............5

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING—ON-BOARD

DIAGNOSTICS (OBD) ...................5

DIAGNOSIS AND TESTING—COOLING

SYSTEM - TESTING FOR LEAKS ..........5

DIAGNOSIS AND TESTING - COOLING

SYSTEM DIESEL ENGINE ................7

DIAGNOSIS AND TESTING - PRELIMINARY

CHECKS ............................10

STANDARD PROCEDURE

STANDARD PROCEDURE - COOLANT

LEVEL CHECK........................17

STANDARD PROCEDURE - COOLING

SYSTEM CLEANING/REVERSE FLUSHING . . 17

STANDARD PROCEDURE—DRAINING

COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE . . 18

STANDARD PROCEDURE - REFILLING

COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE . . 18

STANDARD PROCEDURE—DRAINING

COOLING SYSTEM 5.9L/8.0L ENGINE......18

STANDARD PROCEDURE—REFILLING

COOLING SYSTEM 5.9L/8.0L ENGINE......18

STANDARD PROCEDURE—DRAINING

COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19

STANDARD PROCEDURE—REFILLING

COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19

STANDARD PROCEDURE - ADDING

ADDITIONAL COOLANT.................19

SPECIFICATIONS

TORQUE ............................20

SPECIFICATIONS - ....................20

SPECIAL TOOLS

COOLING ...........................20

ACCESSORY DRIVE ......................22

ENGINE ...............................35

TRANSMISSION .........................72

COOLING

DESCRIPTION

DESCRIPTION - COOLING SYSTEM FLOW

3.7L/4.7L ENGINE

The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible. It also maintains normal operating temperature and prevents overheating.

The cooling system provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system is pressurized and uses a centrifugal water pump to circulate coolant through the system and a coolant deaeration and reserve system that utilizes a pressurized degas bottle (hot bottle).

An optional factory installed maximum duty cooling package is available on most models. This package will provide additional cooling capacity for

vehicles used under extreme conditions such as trailer towing in high ambient temperatures (Fig. 1).

DESCRIPTION - COOLING SYSTEM FLOW -

5.9L ENGINE

The cooling system also provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system uses a coolant recovery / reserve system that utilizes an ambient overflow bottle.

An optional factory installed maximum duty cooling package is available on most models. This package will provide additional cooling capacity for vehicles used under extreme conditions such as trailer towing in high ambient temperatures (Fig. 2).

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Fig. 1 Engine Cooling System Flow - 3.7L/4.7L

1 - LH CYL. HEAD 2 - BLEED 3 - THERMOSTAT LOCATION 4 - RH CYL. HEAD 5 - RH BANK CYL. BLOCK

DESCRIPTION—COOLING SYSTEM FLOW -

5.9L DIESEL

The diesel engine cooling system consists of :

• Cross-flow radiator

• Belt driven water pump

• Belt driven mechanical cooling fan

• Electronic viscous fan drive

• Fan shroud

• Radiator pressure cap

6 - LH BANK CYL. BLOCK 7 - COOLANT TEMP. SENSOR 8 - FROM HEATER CORE 9 - TO HEATER CORE

• Vertically mounted thermostat

• Coolant reserve/recovery system

• Transmission oil cooler

• Coolant

Coolant flow circuits for the 5.9L diesel engine are shown in (Fig. 3).

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DR COOLING 7 - 3

COOLING (Continued)

Fig. 2 ENGINE COOLING SYSTEM FLOW - 5.9L

1 - HEATER 2 - BYPASS*

DESCRIPTION - HOSE CLAMPS

The cooling system utilizes spring type hose clamps. If a spring type clamp replacement is necessary, replace with the original Mopart equipment spring type clamp.

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only a original equipment clamp with matching number or letter and ensure the clamp has the same size width (Fig. 4).

3 - CROSSFLOW RADIATOR 4 - THERMOSTAT LOCATION

OPERATION

OPERATION—COOLING SYSTEM

The cooling system also provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling

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COOLING (Continued)

Fig. 3 Cooling System Circulation—Diesel Engine

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COOLING (Continued)

• If an open or shorted condition has developed in the electronically controlled viscous fan clutch circuit, a Diagnostic Trouble Code (DTC) can be set.

• If fan speed is not detected a DTC will be set.

• Coolant temperature sensor circuit problems can

set a DTC.

If the problem is sensed in a monitored circuit often enough to indicated an actual problem, a DTC is stored. The DTC will be stored in the ECM memory for eventual display to the service technician. (Refer to 25 - EMISSIONS CONTROL - DESCRIPTION).

ACCESSING DIAGNOSTIC TROUBLE CODES

To read DTC’s and to obtain cooling system data, (Refer to 25 - EMISSIONS CONTROL - DESCRIPTION).

Fig. 4 Spring Clamp Size Location

1 - SPRING CLAMP SIZE LOCATION

system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system.

5.9L, 5.9L Diesel, and 8.0L engines utilize an ambient overflow bottle for coolant recovery/reserve. The 3.7L and 4.7L engines utilize a pressurized degas bottle for coolant deaeration and reserve. This degas bottle has coolant flowing through it continuously, supplied by a vent in the hot side radiator tank and returning to the heater return hose.

OPERATION—HOSE CLAMPS

The spring type hose clamp applies constant tension on a hose connection. To remove a spring type hose clamp, only use constant tension clamp pliers designed to compress the hose clamp.

ERASING TROUBLE CODES

After the problem has been repaired, use the DRBIIIt scan tool to erase a DTC. Refer to the appropriate Powertrain Diagnostic Procedures service information for operation of the DRBIIIt scan tool.

DIAGNOSIS AND TESTING—COOLING SYSTEM

- TESTING FOR LEAKS

ULTRAVIOLET LIGHT METHOD

A leak detection additive is available through the parts department that can be added to cooling system. The additive is highly visible under ultraviolet light (black light). Pour one ounce of additive into cooling system. Place heater control unit in HEAT position. Start and operate the engine until the radiator upper hose is warm to the touch. Aim the commercially available black light tool at the components to be checked. If leaks are present, the black light will cause the additive to glow a bright green color.

The black light can be used in conjunction with a pressure tester to determine if any external leaks exist (Fig. 5).

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING—ON-BOARD DIAGNOSTICS (OBD)

COOLING SYSTEM RELATED DIAGNOSTICS

The Engine Control Module (ECM) has been programmed to monitor certain cooling system components:

• If the engine has remained cool for too long a period, such as with a stuck open thermostat, a Diagnostic Trouble Code (DTC) can be set.

PRESSURE TESTER METHOD

The engine should be at normal operating temperature. Recheck the system cold if the cause of coolant loss is not located during the warm engine examination.

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING.

Carefully remove the radiator pressure cap from the filler neck and check the coolant level. Push down on the cap to disengage it from the stop tabs. Wipe the inside of the filler neck and examine the

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COOLING (Continued)

Drops Quickly: Indicates that serious leakage is occurring. Examine the system for external leakage. If leaks are not visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.

INTERNAL LEAKAGE INSPECTION

Remove the engine oil pan drain plug and drain a small amount of engine oil. If coolant is present in the pan, it will drain first because it is heavier than oil. An alternative method is to operate engine for a short period to churn the oil. After this is done, remove the engine dipstick and inspect for water globules. Also inspect the transmission dipstick for water globules and transmission fluid cooler for leakage.

WARNING: WITH RADIATOR PRESSURE TESTER TOOL INSTALLED ON RADIATOR, DO NOT ALLOW PRESSURE TO EXCEED 145 kPa (21 PSI). PRESSURE WILL BUILD UP QUICKLY IF A COMBUSTION LEAK IS PRESENT. TO RELEASE PRESSURE,

Fig. 5 Leak Detection Using Black Light—Typical

1 - TYPICAL BLACK LIGHT TOOL

lower inside sealing seat for nicks, cracks, paint, dirt and solder residue. Inspect the radiator-to- reserve/ overflow tank hose for internal obstructions. Insert a wire through the hose to be sure it is not obstructed.

Inspect the cams on the outside of the filler neck. If the cams are damaged, seating of the pressure cap valve and tester seal will be affected.

Attach pressure tester (7700 or an equivalent) to radiator filler neck.

Operate the tester pump to apply 103.4 kPa (15 psi) pressure to the system. If the hoses enlarge excessively or bulges while testing, replace as necessary. Observe the gauge pointer and determine the condition of the cooling system according to following criteria:

Holds Steady: If the pointer remains steady for two minutes, serious coolant leaks are not present in system. However, there could be an internal leak that does not appear with normal system test pressure. If it is certain that coolant is being lost and leaks cannot be detected, inspect for interior leakage or perform Internal Leakage Test. Refer to INTERNAL LEAKAGE INSPECTION.

Drops Slowly: Indicates a small leak or seepage is occurring. Examine all of the connections for seepage or slight leakage with a flashlight. Inspect the radiator, hoses, gasket edges and heater. Seal the small leak holes with a Sealer Lubricant (or equivalent). Repair the leak holes and inspect the system again with pressure applied.

ROCK TESTER FROM SIDE TO SIDE. WHEN REMOVING TESTER, DO NOT TURN TESTER MORE THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.

Operate the engine without the pressure cap on the radiator until the thermostat opens. Attach a Pressure Tester to the filler neck. If pressure builds up quickly it indicates a combustion leak exists. This is usually the result of a cylinder head gasket leak or crack in engine. Repair as necessary.

If there is not an immediate pressure increase, pump the Pressure Tester. Do this until indicated pressure is within system range of 110 kPa (16 psi). Fluctuation of the gauge pointer indicates compression or combustion leakage into cooling system.

Because the vehicle is equipped with a catalytic converter, do not short out cylinders to isolate compression leak.

If the needle on dial of the pressure tester does not fluctuate, race engine a few times to check for an abnormal amount of coolant or steam. This would be emitting from exhaust pipe. Coolant or steam from exhaust pipe may indicate a faulty cylinder head gasket, cracked engine cylinder block or cylinder head.

A convenient check for exhaust gas leakage into cooling system is provided by a commercially available Block Leak Check tool. Follow manufacturers instructions when using this product.

COMBUSTION LEAKAGE TEST—WITHOUT PRESSURE TESTER

DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

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DR COOLING 7 - 7

COOLING (Continued)

WARNING: DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAINCOCK WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

Drain sufficient coolant to allow thermostat removal. (Refer to 7 - COOLING/ENGINE/ENGINE COOLANT THERMOSTAT - REMOVAL). Remove accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).

Add coolant to radiator to bring level to within 6.3 mm (1/4 in) of the top of the thermostat housing.

DIAGNOSIS AND TESTING - COOLING SYSTEM DIESEL ENGINE

COOLING SYSTEM DIAGNOSIS—DIESEL ENGINE

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READS LOWNOTE: Information on dash cluster is displayed based on broadcast data from ECM. DTC will be set for engine sensor circuit concern.

1. Vehicle is equipped with a heavy duty cooling system.

2. Thermostat stuck open 2. Inspect and test thermostat.

3. Coolant level low. 3. Fill cooling system. (Refer to 7 -

4. Temperature gauge not functioning correctly.

CAUTION: Avoid overheating. Do not operate engine for an excessive period of time. Open draincock immediately after test to eliminate boil over.

Start engine and accelerate rapidly three times, to approximately 3000 rpm while observing coolant. If internal engine combustion gases are leaking into cooling system, bubbles will appear in coolant. If bubbles do not appear, internal combustion gas leakage is not present.

1. None. System operating normally.

COOLING - STANDARD PROCEDURE)

4. Check cluster (Refer to 8 ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING)

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COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READS HIGH. COOLANT MAY OR MAY NOT BE LEAKING FROM SYSTEMNOTE: Information on dash cluster is displayed based on broadcast data from ECM. DTC will be set for engine sensor circuit concern.

1. Vehicle overloaded, high ambient (outside) temperatures with A/C turned on, stop and go driving or prolonged operation at idle speeds.

2. Temperature gauge not functioning correctly.

3. Air trapped in cooling system 3. Drain cooling system (Refer to 7 -

4. Radiator cap faulty. 4. Replace radiator cap.

5. Plugged A/C or radiator cooling fins.

6. Coolant mixture incorrect. 6. Drain cooling system (Refer to 7 -

7. Thermostat stuck shut. 7. Inspect and test thermostat.

8. Bug screen or winter front being used.

9. Electronically controlled viscous fan drive not operating properly.

10. Cylinder head gasket leaking. 10. Check for leaking head gaskets

11. Heater core leaking. 11. Replace heater core.

12. Cooling system hoses leaking. 12. Tighten clamps or Replace

13. Brakes dragging. 13. Check brakes. (Refer to 5 -

14. Accessory drive belt. 14. Inspect. Replace as necessary.

15. Water Pump. 15. Inspect and replace as

1. Temporary condition, repair not required. Notify customer of vehicle operation instructions located in Owners Manual.

2. Check cluster (Refer to 8 ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING)

COOLING - STANDARD PROCEDURE) and refill (Refer to 7

- COOLING - STANDARD PROCEDURE)

5. Clean all debris away from A/C and radiator cooling fins.

COOLING - STANDARD PROCEDURE) refill with correct mixture (Refer to 7 - COOLING STANDARD PROCEDURE).

Replace thermostat if necessary.

8. Remove bug screen or winter front.

9. Check viscous fan (Refer to 7 COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING)

(Refer to 7 - COOLING DIAGNOSIS AND TESTING).

hoses.

BRAKES/HYDRAULIC/ MECHANICAL - DIAGNOSIS AND TESTING)

necessary.

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DR COOLING 7 - 9

COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READING INCONSISTENT (ERRATIC, CYCLES OR FLUCTUATES)NOTE: Information on dash cluster is displayed based on broadcast data from ECM. DTC will be set for engine sensor circuit concern.

RADIATOR CAP LEAKING STEAM AND /OR COOLANT INTO RESERVOIR BOTTLE. (TEMPERATURE GAUGE MAY READ HIGH)

1. Heavy duty cooling system, extreme cold ambient (outside) temperature or heater blower motor in high position.

2. Temperature gauge or sensor defective.

3. Temporary heavy usage or load. 3. None. Normal condition.

4. Air trapped in cooling system. 4. Fill cooling system (Refer to 7 -

5. Water pump 5. Replace water pump.

6. Air leak on suction side of water pump.

1. Radiator cap defective. 1. Replace radiator cap.

2. Radiator neck surface damaged. 2. Replace radiator.

1. None. System operating normally.

2. Check cluster or engine coolant temp sensor (Refer to 8 ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING)

COOLING - STANDARD PROCEDURE).

6. Check for leak. (Refer to 7 COOLING - DIAGNOSIS AND TESTING)

HOSE OR HOSES COLLAPSE WHEN ENGINE IS COOLING.

NOISY FAN 1. Fan blade(s) loose, damaged. 1. Replace fan blade assembly.

1. Vacuum created in cooling system on engine cool-down is not being relieved through coolant reservoir/overflow system.

2. Electronically controlled viscous fan drive.

3. Fan blades striking surrounding objects.

4. Electronically controlled viscous fan drive bearing.

5. Electronically controlled viscous fan stuck on

6. Obstructed air flow through radiator.

1. Replace radiator cap, check vent hose between radiator and reservoir bottle for blockage also check reservoir bottle vent for blockage.

2. None. Normal condition.

3. Locate contact point and repair as necessary.

4. Check viscous fan (Refer to 7 COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING)

5. Check viscous fan (Refer to 7 COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING)

6. Remove obstruction.

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COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

INADEQUATE AIR CONDITIONER PERFORMANCE (COOLING SYSTEM SUSPECTED)

INADEQUATE HEATER PERFORMANCE. GAUGE MAY OR MAY NOT READ LOW.

HEAT ODOR 1. Damaged or missing drive line

1. Radiator and/or A/C condenser air flow obstructed.

2. Electronically controlled viscous fan drive not working.

3. Air seals around radiator damaged or missing.

1. Heavy duty cooling system, and cooler ambient temperatures.

2. Obstruction in heater hoses. 2. Remove hoses, remove

3. Electronically controlled viscous fan stuck on

4. Water pump damaged. 4. Replace water pump.

heat shields.

2. Electronically controlled viscous fan drive damaged.

1. Remove obstruction and/or clean.

2. Check fan drive. (Refer to 7 COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING)

3. Inspect air seals, repair or replace as necessary.

1. None. Normal condition.

obstruction. Check fan drive. (Refer to 7 -

COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING)

1. Repair or replace damaged or missing heat shields.

2. Check thermal viscous fan drive. (Refer to 7 - COOLING/ENGINE/ FAN DRIVE VISCOUS CLUTCH DIAGNOSIS AND TESTING)

DIAGNOSIS AND TESTING - PRELIMINARY CHECKS

ENGINE COOLING SYSTEM OVERHEATING

Establish what driving conditions caused the complaint. Abnormal loads on the cooling system such as the following may be the cause:

• PROLONGED IDLE

• VERY HIGH AMBIENT TEMPERATURE

• SLIGHT TAIL WIND AT IDLE

• SLOW TRAFFIC

• TRAFFIC JAMS

• HIGH SPEED OR STEEP GRADES

Driving techniques that avoid overheating are:

• Idle with A/C off when temperature gauge is at

end of normal range.

• Increasing engine speed for more air flow is rec-

ommended.

TRAILER TOWING:

Consult Trailer Towing section of owners manual. Do not exceed limits.

RECENT SERVICE OR ACCIDENT REPAIR:

Determine if any recent service has been performed on vehicle that may effect the cooling system. This may be:

• Engine adjustments (incorrect timing)

• Slipping engine accessory drive belt(s)

• Brakes (possibly dragging)

• Changed parts. Incorrect water pump or pump

rotating in wrong direction due to belt not correctly routed

• Reconditioned radiator or cooling system refill-

ing (possibly under filled or air trapped in system).

• Service to electrically controlled viscous fan

clutch

NOTE: If investigation reveals none of the previous items as a cause for an engine overheating complaint, refer to COOLING SYSTEM DIAGNOSIS CHART BELOW.

These charts are to be used as a quick-reference only. Refer to COOLING SYSTEM DIAGNOSIS CHART

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COOLING (Continued)

COOLING SYSTEM DIAGNOSIS CHART

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READS LOW

1. Has a Diagnostic Trouble Code (DTC) been set indicating a stuck open thermostat?

2. Is the temperature sending unit connected?

3. Is the temperature gauge operating OK?

4. Coolant level low in cold ambient temperatures accompanied with poor heater performance.

5. Improper operation of internal heater doors or heater controls.

1. (Refer to 25 - EMISSIONS CONTROL DESCRIPTION) for On-Board Diagnostics and DTC information. Replace thermostat if necessary.

2. Check the temperature sensor connector. (Refer to 8 - ELECTRICAL/ INSTRUMENT CLUSTER - SCHEMATIC ELECTRICAL) Repair connector if necessary.

3. Check gauge operation. (Refer to 8 ELECTRICAL/INSTRUMENT CLUSTER/ ENGINE TEMPERATURE GAUGE DESCRIPTION). Repair as necessary.

4. Check coolant level in the coolant reserve/overflow tank or degas bottle and the radiator. Inspect system for leaks. Repair leaks as necessary. Refer to the Coolant section of the manual text for WARNINGS and CAUTIONS associated with removing the radiator cap.

5. Inspect heater and repair as necessary. (Refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING) for procedures.

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COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READS HIGH OR THE COOLANT WARNING LAMP ILLUMINATES. COOLANT MAY OR MAY NOT BE LOST OR LEAKING FROM THE COOLING SYSTEM

1. Trailer is being towed, a steep hill is being climbed, vehicle is operated in slow moving traffic, or engine is being idled with very high ambient (outside) temperatures and the air conditioning is on. Higher altitudes could aggravate these conditions.

2. Is the temperature gauge reading correctly?

3. Is the temperature warning illuminating unnecessarily?

4. Coolant low in coolant reserve/overflow tank and radiator?

5. Pressure cap not installed tightly. If cap is loose, boiling point of coolant will be lowered. Also refer to the following Step

6. Poor seals at the radiator cap.

7. Coolant level low in radiator but not in coolant reserve/ overflow tank. This means the radiator is not drawing coolant from the coolant reserve/ overflow tank as the engine cools (5.9L).

8. Incorrect coolant concentration

9. Coolant not flowing through system

1. This may be a temporary condition and repair is not necessary. Turn off the air conditioning and attempt to drive the vehicle without any of the previous conditions. Observe the temperature gauge. The gauge should return to the normal range. If the gauge does not return to the normal range, determine the cause for overheating and repair. Refer to Possible Causes (2-18).

2. Check gauge. (Refer to 8 ELECTRICAL/INSTRUMENT CLUSTER SCHEMATIC - ELECTRICAL). Repair as necessary.

3. (Refer to 8 - ELECTRICAL/ INSTRUMENT CLUSTER - SCHEMATIC ELECTRICAL).

4. Check for coolant leaks and repair as necessary. (Refer to 7 - COOLING DIAGNOSIS AND TESTING).

5. Tighten cap

6. (a) Check condition of cap and cap seals. Refer to Radiator Cap. Replace cap if necessary.

(b) Check condition of radiator filler neck. If neck is bent or damaged, replace radiator (5.9L) or degas bottle (3.7L, 4.7L).

7. (a) Check condition of radiator cap and cap seals. Refer to Radiator Cap in this Group. Replace cap if necessary.

(b) Check condition of radiator filler neck. If neck is bent or damaged, replace radiator.

(c) Check condition of the hose from the radiator to the coolant tank. It should fit tight at both ends without any kinks or tears. Replace hose if necessary.

(d) Check coolant reserve/overflow tank and tanks hoses for blockage. Repair as necessary.

8. Check coolant. (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES DESCRIPTION).

9. Check for coolant flow at radiator filler neck with some coolant removed, engine warm and thermostat open. Coolant should be observed flowing through radiator. If flow is not observed, determine area of obstruction and repair as necessary.

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DR COOLING 7 - 13

COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

10. Radiator or A/C condenser fins are dirty or clogged.

11. Radiator core is corroded or plugged.

12. Fuel or ignition system problems.

13. Dragging brakes. 13. Check and correct as necessary.

14. Bug screen or cardboard is being , reducing airflow.

15. Thermostat partially or completely shut.

16. Viscous fan drive not operating properly.

17. Cylinder head gasket leaking.

18. Heater core leaking. 18. Check heater core for leaks. (Refer to

10. Remove insects and debris. (Refer to 7 - COOLING - STANDARD PROCEDURE).

11. Have radiator re-cored or replaced.

12. Refer to 14 - Fuel System or 8 Electrical for diagnosis and testing procedures.

(Refer to 5 - BRAKES - DIAGNOSIS AND TESTING) for correct procedures.

14. Remove bug screen or cardboard.

15. Check thermostat operation and replace as necessary. (Refer to 7 COOLING/ENGINE/ENGINE COOLANT THERMOSTAT - REMOVAL) .

16. Check fan drive operation and replace as necessary. (Refer to 7 - COOLING/ ENGINE/FAN DRIVE VISCOUS CLUTCH

- REMOVAL).

17. Check for cylinder head gasket leaks. (Refer to 7 - COOLING - DIAGNOSIS AND TESTING).

24 - HEATING & AIR CONDITIONING/ PLUMBING - DIAGNOSIS AND TESTING). Repair as necessary.

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7 - 14 COOLING DR

COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

Temperature gauge reading is inconsistent (flucttuates, cycles or is erratic)

1. During cold weather operation, with the heater blower in the high position, the gauge reading may drop slightly.

2. Temperature gauge or engine mounted gauge sensor defective or shorted. Also, corroded or loose wiring in this circuit.

3. Gauge reading rises when vehicle is brought to a stop after heavy use (engine still running)

4. Gauge reading high after re-starting a warmed up (hot) engine.

5. Coolant level low in radiator (air will build up in the cooling system causing the thermostat to open late).

6. Cylinder head gasket leaking allowing exhaust gas to enter cooling system causing a thermostat to open late.

7. Water pump impeller loose on shaft.

8. Loose accessory drive belt. (water pump slipping)

9. Air leak on the suction side of the water pump allows air to build up in cooling system causing thermostat to open late.

1. A normal condition. No correction necessary.

2. Check operation of gauge and repair if necessary. (Refer to 8 - ELECTRICAL/ INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).

3. A normal condition. No correction is necessary. Gauge should return to normal range after vehicle is driven.

4. A normal condition. No correction is necessary. The gauge should return to normal range after a few minutes of engine operation.

5. Check and correct coolant leaks. (Refer to 7 - COOLING - DIAGNOSIS AND TESTING).

6. (a) Check for cylinder head gasket leaks. (Refer to 7 - COOLING DIAGNOSIS AND TESTING).

(b) Check for coolant in the engine oil. Inspect for white steam emitting from the exhaust system. Repair as necessary.

7. Check water pump and replace as necessary. (Refer to 7 - COOLING/ ENGINE/WATER PUMP - REMOVAL).

8. (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - DIAGNOSIS AND TESTING). Check and correct as necessary.

9. Locate leak and repair as necessary.

PRESSURE CAP IS BLOWING OFF STEAM AND/OR COOLANT TO COOLANT TANK. TEMPERATURE GAUGE READING MAY BE ABOVE NORMAL BUT NOT HIGH. COOLANT LEVEL MAY BE HIGH IN COOLANT RESERVE/ OVERFLOW TANK

COOLANT LOSS TO THE GROUND WITHOUT PRESSURE CAP BLOWOFF. GAUGE READING HIGH OR HOT

1. Pressure relief valve in radiator cap is defective.

1. Coolant leaks in radiator, cooling system hoses, water pump or engine.

1. Check condition of radiator cap and cap seals. (Refer to 7 - COOLING/ENGINE/ RADIATOR PRESSURE CAP DIAGNOSIS AND TESTING). Replace cap as necessary.

1. Pressure test and repair as necessary. (Refer to 7 - COOLING - DIAGNOSIS AND TESTING).

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DR COOLING 7 - 15

COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

DETONATION OR PREIGNITION (NOT CAUSED BY IGNITION SYSTEM). GAUGE MAY OR MAY NOT BE READING HIGH

HOSE OR HOSES COLLAPSE WHILE ENGINE IS RUNNING

(b) Hose between coolant reserve/overflow tank and radiator is kinked. Repair as necessary.

NOISY VISCOUS FAN/DRIVE 1. Fan blades loose. 1. Replace fan blade assembly. (Refer to 7

1. Engine overheating. 1. Check reason for overheating and repair as necessary.

2. Freeze point of coolant not

correct. Mixture is too rich or too lean.

1. Vacuum created in cooling

system on engine cool-down is not being relieved through coolant reserve/overflow system.

2. Fan blades striking a

surrounding object.

3. Air obstructions at radiator or

air conditioning condenser.

4. Thermal viscous fan drive has

defective bearing.

5. A certain amount of fan noise

may be evident on models equipped with a thermal viscous fan drive. Some of this noise is normal.

2. Check coolant concentration. (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION).

1. (a) Radiator cap relief valve stuck. (Refer to 7 - COOLING/ENGINE/ RADIATOR PRESSURE CAP DIAGNOSIS AND TESTING). Replace if necessary

(d) Reserve/overflow tank is internally blocked or plugged. Check for blockage and repair as necessary.

- COOLING/ENGINE/RADIATOR FAN REMOVAL)

2. Locate point of fan blade contact and repair as necessary.

3. Remove obstructions and/or clean debris or insects from radiator or A/C condenser.

4. Replace fan drive. Bearing is not serviceable. (Refer to 7 - COOLING/ ENGINE/FAN DRIVE VISCOUS CLUTCH

- REMOVAL).

5. (Refer to 7 - COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH DESCRIPTION) for an explanation of normal fan noise.

Page 16

7 - 16 COOLING DR

COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

INADEQUATE HEATER PERFORMANCE. THERMOSTAT FAILED IN OPEN POSITION

STEAM IS COMING FROM THE FRONT OF VEHICLE NEAR THE GRILL AREA WHEN WEATHER IS WET, ENGINE IS WARMED UP AND RUNNING, AND VEHICLE IS STATIONARY. TEMPERATURE GAUGE IS IN NORMAL RANGE

1. Has a Diagnostic trouble

Code (DTC) been set?

2. Coolant level low 2. (Refer to 7 - COOLING - DIAGNOSIS

3. Obstructions in heater

hose/fittings

4. Heater hose kinked 4. Locate kinked area and repair as

5. Water pump is not pumping

water to/through the heater core. When the engine is fully warmed up, both heater hoses should be hot to the touch. If only one of the hoses is hot, the water pump may not be operating correctly or the heater core may be plugged. Accessory drive belt may be slipping causing poor water pump operation.

1. During wet weather, moisture

(snow, ice or rain condensation) on the radiator will evaporate when the thermostat opens. This opening allows heated water into the radiator. When the moisture contacts the hot radiator, steam may be emitted. This usually occurs in cold weather with no fan or airflow to blow it away.

1. (Refer to 25 - EMISSIONS CONTROL DESCRIPTION) for correct procedures and replace thermostat if necessary

AND TESTING).

3. Remove heater hoses at both ends and check for obstructions

necessary

5. (Refer to 7 - COOLING/ENGINE/ WATER PUMP - REMOVAL). If a slipping belt is detected, (Refer to 7 - COOLING/ ACCESSORY DRIVE/DRIVE BELTS DIAGNOSIS AND TESTING). If heater core obstruction is detected, (Refer to 24 HEATING & AIR CONDITIONING/ PLUMBING/HEATER CORE - REMOVAL).

1. Occasional steam emitting from this area is normal. No repair is necessary.

COOLANT COLOR 1. Coolant color is not

necessarily an indication of adequate corrosion or temperature protection. Do not rely on coolant color for determining condition of coolant.

COOLANT LEVEL CHANGES IN COOLANT RESERVE/ OVERFLOW TANK. TEMPERATURE GAUGE IS IN NORMAL RANGE

1. Level changes are to be

expected as coolant volume fluctuates with engine temperature. If the level in the tank was between the FULL and ADD marks at normal operating temperature, the level should return to within that range after operation at elevated temperatures.

1. (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES DESCRIPTION). Adjust coolant mixture as necessary.

1. A normal condition. No repair is necessary.

Page 17

DR COOLING 7 - 17

COOLING (Continued)

STANDARD PROCEDURE

STANDARD PROCEDURE - COOLANT LEVEL CHECK

NOTE: Do not remove radiator cap for routine coolant level inspections. The coolant level can be checked at coolant recovery bottle or the coolant degas bottle.

WARNING: DO NOT REMOVE OR LOOSEN THE RADIATOR CAP WITH THE COOLING SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT OR HIGH PRESSURE STEAM CAN OCCUR.

The 5.9L, 5.9L Diesel, and 8.0L engine coolant reserve / overflow system provides a quick method for determining the coolant level without removing the radiator pressure cap. With the engine at normal operating temperature and idling, observe the level of the coolant on the external level indicator on the side of the coolant reserve / overflow bottle. The coolant level should be between the MIN and MAX marks. If the coolant is below the MIN mark, add a 50/50 mixture of antifreeze and water to the bottle until the level reaches the MIN mark. Do Not Over-

fill the bottle by adding fluid above the MAX line. This may cause coolant to spill onto the ground

during subsequent vehicle operation.

The 3.7L/4.7L/5.9L engine coolant degas system provides a quick method for determining the coolant level with out removing the radiator pressure cap. With a cold engine, observe the level of coolant in the degas bottle. The level should be in the COLD FILL RANGE. DO NOT OVERFILL the bottle by adding fluid above the COLD FILL RANGE. This may cause coolant to spill onto the ground during subsequent vehicle operation.

STANDARD PROCEDURE - COOLING SYSTEM CLEANING/REVERSE FLUSHING

CLEANING

Drain the cooling system and refill with water. Run the engine with the radiator cap installed until the upper radiator hose is hot. Stop the engine and drain the water from system. If the water is dirty, fill the system with water, run the engine and drain the system. Repeat this procedure until the water drains clean.

REVERSE FLUSHING

Reverse flushing of the cooling system is the forcing of water through the cooling system. This is done

using air pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with evidence of partial plugging.

REVERSE FLUSHING RADIATOR

Disconnect the radiator hoses from the radiator inlet and outlet. Attach a section of the radiator hose to the radiator bottom outlet fitting and insert the flushing gun. Connect a water supply hose and air supply hose to the flushing gun.

CAUTION: Internal radiator pressure must not exceed 138 kPa (20 psi) as damage to radiator may result.

Allow the radiator to fill with water. When the radiator is filled, apply air in short blasts. Allow the radiator to refill between blasts. Continue this reverse flushing until clean water flows out through the rear of the radiator cooling tube passages.

REVERSE FLUSHING ENGINE

Drain the cooling system. Remove the thermostat housing and thermostat. Install the thermostat housing. Disconnect the radiator upper hose from the radiator and attach the flushing gun to the hose. Disconnect the radiator lower hose from the water pump and attach a lead-away hose to the water pump inlet fitting.

CAUTION: On vehicles equipped with a heater water control valve, be sure the heater control valve is closed (heat off). This will prevent coolant flow with scale and other deposits from entering the heater core.

Connect the water supply hose and air supply hose to flushing gun. Allow the engine to fill with water. When the engine is filled, apply air in short blasts, allowing the system to fill between air blasts. Continue until clean water flows through the lead away hose.

Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing and install the thermostat. Install the thermostat housing with a replacement gasket. Refer to Thermostat Replacement. Connect the radiator hoses. Refill the cooling system with the correct antifreeze/water mixture. Refer to Refilling the Cooling System.

CHEMICAL CLEANING

In some instances, use a radiator cleaner (Mopart Radiator Kleen or equivalent) before flushing. This will soften scale and other deposits and aid flushing operation.

Page 18

7 - 18 COOLING DR

COOLING (Continued)

CAUTION: Follow manufacturers instructions when using these products.

STANDARD PROCEDURE—DRAINING COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE

WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS (Fig. 6) OR LOOSEN THE RADIATOR DRAINCOCK WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

(1) With the engine cold, raise the vehicle on a

hoist and locate the radiator draincock.

NOTE: Radiator draincock is located on the left/ lower side of radiator facing to rear of vehicle.

(2) Attach one end of a hose to the draincock. Put the other end into a clean container. Remove the radiator cap, open the draincock and drain the cooling system.

(3) If draining the entire engine is required, remove the cylinder block drain plugs.

(1) Install the cylinder block drain plugs (if removed). Coat the threads with Mopart Thread Sealant with Teflon.

(2) Close the radiator draincock.

CAUTION: Failure to purge air from the cooling system can result in an overheating condition and severe engine damage.

(3) Fill system using a 50/50 mixture antifreeze and low mineral content water. Stop filling when the level in the degas bottle has reached the top of the COLD FILL RANGE.

(4) Start and operate the engine until the thermostat opens (upper radiator hose is warm to the touch).

(5) If necessary, add a 50/50 mixture of anti-freeze and water to the degass bottle to maintain the proper coolant level in the degas bottle.

(6) Install the radiator cap.

STANDARD PROCEDURE—DRAINING COOLING SYSTEM 5.9L/8.0L ENGINE

WARNING: DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAINCOCK WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

Fig. 6 Drain Plug - 3.7L/4.7L Engine

1 - CYLINDER BLOCK DRAIN PLUG 2 - EXHAUST MANIFOLD AND HEAT SHIELD

STANDARD PROCEDURE - REFILLING COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE

DO NOT WASTE REUSABLE COOLANT.Ifthe solution is clean, drain the coolant into a clean container for reuse.

DO NOT WASTE reusable coolant. If solution is

clean, drain coolant into a clean container for reuse.

(1) Attach one end of a hose to the draincock. Put

the other end into a clean container.

(2) DO NOT REMOVE THE RADIATOR CAP when draining the coolant from the reservoir/overflow tank. Open radiator draincock and when the tank is empty, remove the radiator cap and continue draining the cooling system.

(3) If draining the entire engine, remove the cylinder block drain plugs. Refer to (Fig. 7).

STANDARD PROCEDURE—REFILLING COOLING SYSTEM 5.9L/8.0L ENGINE

WARNING: DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAINCOCK WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

Clean cooling system prior to refilling. (Refer to 7 COOLING - STANDARD PROCEDURE).

(1) Install cylinder block drain plugs. Coat the threads with Mopart Thread Sealant with Teflon.

(2) Close radiator petcock.

Page 19

DR COOLING 7 - 19

COOLING (Continued)

STANDARD PROCEDURE—REFILLING COOLING SYSTEM 5.9L DIESEL ENGINE

Clean cooling system prior to refilling (Refer to 7 COOLING - STANDARD PROCEDURE).

(1) Close radiator drain plug.

CAUTION: Due to the use of the one-way check valve, the engine must not be operating when refilling the cooling system.

NOTE: The diesel engine is equipped with two oneway check valves (jiggle pins). The check valves are used as a servicing feature and will vent air when the system is being filled. Water pressure (or

Fig. 7 Cylinder Block Drain Plug - 5.9L Engines

1 - BLOCK DRAIN PLUG

(3) Fill cooling system with a 50/50 mixture of

water and antifreeze.

(4) Fill coolant reserve/overflow tank to MAX mark

on bottle.

(5) Start and operate engine until thermostat

opens (upper radiator hose warm to touch).

(6) If necessary, add a 50/50 water and antifreeze mixture to the coolant reserve/overflow tank. This is done to maintain coolant level between the MAX and MIN marks. The level in the reserve/overflow tank may drop below the MIN mark after three or four warm-up and cool-down cycles.

flow) will hold the valves closed.

(2) Fill the cooling system with a 50/50 mixture of

water and antifreeze.

(3) Fill coolant reserve/overflow tank to the FULL

mark.

(4) Start and operate engine until thermostat

opens. Upper radiator hose should be warm to touch.

(5) If necessary, add 50/50 water and antifreeze mixture to the coolant reserve/overflow tank to maintain coolant level. This level should be between the ADD and FULL marks. The level in the reserve/overflow tank may drop below the ADD mark after three or four warm-up and cool-down cycles.

STANDARD PROCEDURE - ADDING ADDITIONAL COOLANT

STANDARD PROCEDURE—DRAINING COOLING SYSTEM 5.9L DIESEL ENGINE

WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAIN PLUG WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

(1) Start the engine and place the heater control temperature selector in the Full-On position.

(2) Turn the ignition off.

(3) Do not remove radiator cap when draining coolant from reserve/overflow tank. Open radiator drain plug and when tank is empty, remove radiator cap. If the coolant reserve/overflow tank does not drain, (Refer to 7 - COOLING - DIAGNOSIS AND TESTING). The coolant need not be removed from tank unless the system is being refilled with fresh mixture.

(4) Remove radiator pressure cap.

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only Mopart Antifreeze/Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with corrosion inhibitors called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

CAUTION: Do not use coolant additives that are claimed to improve engine cooling.

For 5.9L engines, do not remove the radiator cap to add coolant to the system. When adding coolant to maintain the correct level, do so only at the reserve/ overflow bottle. Remove the radiator cap only for testing or when refilling the system after service. Removing the cap unnecessarily can cause loss of coolant and allow air to enter the system, which produces corrosion.

Page 20

7 - 20 COOLING DR

COOLING (Continued)

WARNING: DO NOT REMOVE OR LOOSEN THE RADIATOR CAP WITH THE COOLING SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM THE COOLANT OR HIGH PRESSURE STEAM CAN OCCUR.

For 3.7L / 4.7L/5.9L engines, remove the radiator

cap from the coolant degas bottle to add coolant.

SPECIFICATIONS

TORQUE

DESCRIPTION N·m Ft. In.

Lbs. Lbs.

Automatic Belt Tensioner to Block—Bolts 41 30 —

Automatic Belt Tensioner Pulley—Bolt 61 45 —

Block Heater—Bolt 2 — 17 Generator/Compressor

Mounting Bracket—Bolts

# 1 and 2 54 40 —

# 3 40 30 —

Fan Shroud to Radiator Mounting—Bolts

Radiator to Support - Bolts 8.5 — 75 Fan Blade to Viscous Fan

Drive—Bolts Idler Pulley—Bolt 54 40 — Thermostat Housing—Bolts

- All Except 5.9L Thermostat Housing—Bolts

- 5.9L Power Steering Oil Cooler

— Bolts Transmission Auxiliary Oil

Cooler—Bolts 6 — 55 Transmission Oil Cooler

Tube Nuts Coolant Bottle — Bolts 8.5 — 75 Transmission Oil Cooler to

Transmission - 5.9L/46RE Tube Nuts 31.5 24 —

Transmission Oil Cooler to Transmission - 3.7L/4.7L/ 45RFE - Tube Nuts

Water Pump—Bolts 24 18 — Water Pump — Bolts - 4.7L 58 43 —

6—55

24 18 —

13 — 112

23 16 —

6—55

31.5 24 —

20 18 —

SPECIFICATIONS -

SPECIFICATIONS

DESCRIPTION SPECIFICATION

3.7/4.7L Engine 15.4L (16.2 qts.)- to the middle of the cold fill range

5.7L Engine 15.4L (16.2 qts.)- to the middle of the cold fill range

5.9L Engine 15.5L (16.3 qts.)- to the MIN mark after 3 warm up, cool down cycles

8.0L Engine 24L (25.3 qts.)

5.9L Diesel Engine 28L (29.5 qts.)

SPECIAL TOOLS

COOLING

Pliers Constant Pressure Hose Clamp - 6094

3/8” Quick Connect Release Tool - 6935

SPANNER WRENCH—6958

Page 21

DR COOLING 7 - 21

COOLING (Continued)

Cooling System Pressure Tester - 7700A

Adapter Pins 8346

Page 22

7 - 22 ACCESSORY DRIVE DR

ACCESSORY DRIVE

TABLE OF CONTENTS

page page

BELT TENSIONERS - 3.7L / 4.7L

DESCRIPTION .........................22

OPERATION ...........................22

REMOVAL .............................22

INSTALLATION .........................23

BELT TENSIONERS - 5.9L

DESCRIPTION .........................23

OPERATION ...........................23

REMOVAL .............................23

INSTALLATION .........................24

BELT TENSIONERS - 5.9L DIESEL

DESCRIPTION .........................24

OPERATION ...........................24

REMOVAL .............................25

INSTALLATION .........................25

BELT TENSIONERS - 3.7L /

4.7L

DESCRIPTION

Correct drive belt tension is required to ensure optimum performance of the belt driven engine accessories. If specified tension is not maintained, belt slippage may cause; engine overheating, lack of power steering assist, loss of air conditioning capacity, reduced generator output rate, and greatly reduced belt life.

It is not necessary to adjust belt tension on the

3.7L or 4.7L engine. These engines are equipped with an automatic belt tensioner (Fig. 1). The tensioner maintains correct belt tension at all times. Due to use of this belt tensioner, do not attempt to use a belt tension gauge on 3.7L or 4.7L engines.

OPERATION

The automatic belt tensioner maintains belt tension by using internal spring pressure, a pivoting arm and pulley to press against the drive belt.

REMOVAL

On 3.7L and 4.7L engines, the tensioner is equipped with an indexing tang on back of tensioner and an indexing stop on tensioner housing. If a new belt is being installed, tang must be within approximately 24 mm (.94 inches) of

DRIVE BELTS - 3.7L / 4.7L

DIAGNOSIS AND TESTING - ACCESSORY

DRIVE BELT .........................25

REMOVAL .............................27

INSTALLATION .........................27

DRIVE BELTS - 5.9L

DIAGNOSIS AND TESTING - ACCESSORY

DRIVE BELT .........................28

REMOVAL .............................30

INSTALLATION .........................31

DRIVE BELTS - 5.9L DIESEL

DIAGNOSIS AND TESTING—ACCESSORY

DRIVE BELT .........................31

REMOVAL .............................34

INSTALLATION .........................34

Fig. 1 AUTOMATIC BELT TENSIONER

1 - AUTOMATIC TENSIONER ASSEMBLY

indexing stop. Belt is considered new if it has been used 15 minutes or less.

If the above specification cannot be met, check for:

• The wrong belt being installed (incorrect length/

width)

• Worn bearings on an engine accessory (A/C compressor, power steering pump, water pump, idler pulley or generator)

• A pulley on an engine accessory being loose

• Misalignment of an engine accessory

• Belt incorrectly routed.

Page 23

DR ACCESSORY DRIVE 7 - 23

BELT TENSIONERS - 3.7L / 4.7L (Continued)

NOTE: A used belt should be replaced if tensioner indexing arrow has moved to the minimum tension indicator. Tensioner travel stops at this point.

(1) Remove accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(2) Remove tensioner assembly from mounting bracket (Fig. 2).

BELT TENSIONERS - 5.9L

DESCRIPTION

It is not necessary to adjust belt tension on the

3.9L or 5.9L engines. These engines are equipped with an automatic belt tensioner (Fig. 3). The tensioner maintains correct belt tension at all times. Due to use of this belt tensioner, do not attempt to use a belt tension gauge on 3.9L or 5.9L engines.

Fig. 2 AUTOMATIC BELT TENSIONER - 3.7L/4.7L

ENGINE

1 - TIMING CHAIN COVER 2 - BOLT TORQUE TO 41 N·m (30 FT LBS) 3 - AUTOMATIC BELT TENSIONER

WARNING: BECAUSE OF HIGH SPRING PRESSURE, DO NOT ATTEMPT TO DISASSEMBLE AUTOMATIC TENSIONER. UNIT IS SERVICED AS AN ASSEMBLY EXCEPT FOR PULLEY ON TENSIONER.

(3) Remove pulley bolt. Remove pulley from ten-

sioner.

INSTALLATION

(1) Install pulley and pulley bolt to tensioner.

Tighten bolt to 61 N·m (45 ft. lbs.) torque.

(2) An indexing slot is located on back of tensioner. Align this slot to the head of the bolt on the front cover. Install the mounting bolt. Tighten bolt to 41 N·m (30 ft. lbs.).

(3) Install accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

(4) Check belt indexing marks (Fig. 1).

Fig. 3 Automatic Belt Tensioner - 5.9L Engines

1 - AUTOMATIC TENSIONER 2 - COIL AND BRACKET 3 - SCREW AND WASHER

OPERATION

The automatic belt tensioner maintains belt tension by using internal spring pressure, a pivoting arm and pulley to press against the drive belt.

REMOVAL

WARNING: BECAUSE OF HIGH SPRING PRESSURE, DO NOT ATTEMPT TO DISASSEMBLE AUTOMATIC TENSIONER. UNIT IS SERVICED AS AN ASSEMBLY (EXCEPT FOR PULLEY).

(1) Remove accessory drive belt. (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(2) Disconnect wiring and secondary cable from ignition coil.

(3) Remove ignition coil from coil mounting bracket (two bolts). Do not remove coil mounting bracket from cylinder head.

(4) Remove tensioner assembly from mounting bracket (one nut) (Fig. 4).

Page 24

7 - 24 ACCESSORY DRIVE DR

BELT TENSIONERS - 5.9L (Continued)

BELT TENSIONERS - 5.9L DIESEL

DESCRIPTION

Drive belts on all engines are equipped with a spring loaded automatic belt tensioner (Fig. 5). This tensioner maintains constant belt tension at all times and requires no maintenance or adjustment.

CAUTION: Do not attempt to check belt tension with a belt tension gauge on vehicles equipped with an automatic belt tensioner.

Fig. 4 Tensioner Indexing Marks And Mounting Nut

1 - TENSIONER ASSEMBLY 2 - TENSIONER MOUNTING NUT 3 - INDEXING ARROW 4 - INDEXING MARK

(5) Remove pulley bolt. Remove pulley from ten-

sioner.

INSTALLATION

(1) Install pulley and pulley bolt to tensioner.

Tighten bolt to 61 N·m (45 ft. lbs.) torque.

(2) Install tensioner assembly to mounting bracket. An indexing tab is located on back of tensioner. Align this tab to slot in mounting bracket. Tighten nut to 67 N·m (50 ft. lbs.) torque.

(3) Connect all wiring to ignition coil.

CAUTION: To prevent damage to coil case, coil mounting bolts must be torqued.

(4) Install coil to coil bracket. If nuts and bolts are used to secure coil to coil bracket, tighten to 11 N·m (100 in. lbs.) torque. If coil mounting bracket has been tapped for coil mounting bolts, tighten bolts to 5 N·m (50 in. lbs.) torque.

(5) Install drive belt. (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

(6) Check belt indexing marks (Fig. 4).

Fig. 5 Belt

1 - GENERATOR 2 - WATER PUMP 3 - IDLER 4 - POWER STEERING PUMP 5 - AUTOMATIC TENSIONER 6 - A/C COMPRESSOR

OPERATION

WARNING: THE AUTOMATIC BELT TENSIONER ASSEMBLY IS SPRING LOADED. DO NOT ATTEMPT TO DISASSEMBLE THE TENSIONER ASSEMBLY.

The automatic belt tensioner maintains correct belt tension using a coiled spring within the tensioner housing. The spring applies pressure to the tensioner arm pressing the arm into the belt, tensioning the belt.

Page 25

DR ACCESSORY DRIVE 7 - 25

BELT TENSIONERS - 5.9L DIESEL (Continued)

REMOVAL

WARNING: BECAUSE OF HIGH SPRING PRESSURE, DO NOT ATTEMPT TO DISASSEMBLE AUTOMATIC TENSIONER. UNIT IS SERVICED AS AN ASSEMBLY.

(1) Remove accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(2) Remove tensioner mounting bolt (Fig. 6) and remove tensioner.

DRIVE BELTS - 3.7L / 4.7L

DIAGNOSIS AND TESTING - ACCESSORY DRIVE BELT

VISUAL DIAGNOSIS

When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib (Fig. 7), are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced (Fig. 7). Also replace the belt if it has excessive wear, frayed cords or severe glazing.

Refer to ACCESSORY DRIVE BELT DIAGNOSIS CHART for further belt diagnosis.

Fig. 6 AUTOMATIC BELT TENSIONER DIESEL

ENGINE-TYPICAL

1 - GENERATOR 2 - WATER PUMP 3 - IDLER 4 - POWER STEERING PUMP 5 - AUTOMATIC TENSIONER 6 - A/C COMPRESSOR

INSTALLATION

(1) Install tensioner assembly to mounting bracket. A dowel is located on back of tensioner. Align this dowel to hole in tensioner mounting bracket. Tighten bolt to 43 N·m (32 ft. lbs.) torque.

(2) Install drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

Fig. 7 Belt Wear Patterns

1 - NORMAL CRACKS BELT OK 2 - NOT NORMAL CRACKS REPLACE BELT

NOISE DIAGNOSIS

Noises generated by the accessory drive belt are most noticeable at idle. Before replacing a belt to resolve a noise condition, inspect all of the accessory drive pulleys for alignment, glazing, or excessive end play.

Page 26

7 - 26 ACCESSORY DRIVE DR

DRIVE BELTS - 3.7L / 4.7L (Continued)

ACCESSORY DRIVE BELT DIAGNOSIS CHART

CONDITION POSSIBLE CAUSES CORRECTION

RIB CHUNKING (One or more ribs has separated from belt body)

RIB OR BELT WEAR 1. Pulley misaligned 1. Align pulley(s)

BELT SLIPS 1. Belt slipping because of

1. Foreign objects imbedded in pulley grooves.

2. Installation damage 2. Replace belt

2. Abrasive environment 2. Clean pulley(s). Replace belt if

3. Rusted pulley(s) 3. Clean rust from pulley(s)

4. Sharp or jagged pulley groove tips

5. Belt rubber deteriorated 5. Replace belt

insufficient tension

2. Belt or pulley exposed to substance that has reduced friction (belt dressing, oil, ethylene glycol)

3. Driven component bearing failure (seizure)

4. Belt glazed or hardened from heat and excessive slippage

1. Remove foreign objects from pulley grooves. Replace belt.

necessary

4. Replace pulley. Inspect belt.

1. Inspect/Replace tensioner if necessary

2. Replace belt and clean pulleys

3. Replace faulty component or bearing

4. Replace belt.

LONGITUDAL BELT CRACKING 1. Belt has mistracked from pulley

groove

2. Pulley groove tip has worn away rubber to tensile member

9GROOVE JUMPING9 (Belt does not maintain correct position on pulley)

BELT BROKEN (Note: Identify and correct problem before new belt is installed)

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Pulley(s) not within design tolerance

3. Foreign object(s) in grooves 3. Remove foreign objects from

4. Pulley misalignment 4. Align component

5. Belt cordline is broken 5. Replace belt

1. Incorrect belt tension 1. Replace Inspect/Replace

2. Tensile member damaged during belt installation

3. Severe misalignment 3. Align pulley(s)

4. Bracket, pulley, or bearing failure 4. Replace defective component

1. Replace belt

2. Replace belt

necessary

2. Replace pulley(s)

grooves

tensioner if necessary

2. Replace belt

and belt

Page 27

DR ACCESSORY DRIVE 7 - 27

DRIVE BELTS - 3.7L / 4.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

NOISE (Objectionable squeal, squeak, or rumble is heard or felt while drive belt is in operation)

TENSION SHEETING FABRIC FAILURE (Woven fabric on outside, circumference of belt has cracked or separated from body of belt)

CORD EDGE FAILURE (Tensile member exposed at edges of belt or separated from belt body)

1. Incorrect belt tension 1. Inspect/Replace tensioner if necessary

2. Bearing noise 2. Locate and repair

3. Belt misalignment 3. Align belt/pulley(s)

4. Belt to pulley mismatch 4. Install correct belt

5. Driven component induced

vibration

1. Tension sheeting contacting

stationary object

2. Excessive heat causing woven

fabric to age

3. Tension sheeting splice has

fractured

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Belt contacting stationary object 2. Replace belt

3. Pulley(s) out of tolerance 3. Replace pulley

4. Insufficient adhesion between

tensile member and rubber matrix

5. Locate defective driven component and repair

1. Correct rubbing condition

2. Replace belt

3. Replace belt

necessary

4. Replace belt

REMOVAL

CAUTION: DO NOT LET TENSIONER ARM SNAP BACK TO THE FREEARM POSITION, SEVER DAMAGE MAY OCCUR TO THE TENSIONER.

Belt tension is not adjustable. Belt adjustment is maintained by an automatic (spring load) belt tensioner.

(1) Disconnect negative battery cable from battery.

(2) Rotate belt tensioner until it contacts it’s stop. Remove belt, then slowly rotate the tensioner into the freearm position. (Fig. 8).

INSTALLATION

Belt tension is not adjustable. Belt adjustment is maintained by an automatic ( spring load ) belt tensioner.

(1) Check condition of all pulleys.

CAUTION: When installing the serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction (Fig. 8).

(2) Install new belt (Fig. 8). Route the belt around all pulleys except the idler pulley. Rotate the tensioner arm until it contacts it’s stop position. Route the belt around the idler and slowly let the tensioner rotate into the belt. Make sure the belt is seated onto all pulleys.

(3) With the drive belt installed, inspect the belt wear indicator (Fig. 9). On 4.7L Engines only, the gap between the tang and the housing stop (measurement A) must not exceed 24 mm (.94 inches). If the measurement exceeds this specification replace the serpentine accessory drive belt.

Page 28

7 - 28 ACCESSORY DRIVE DR

DRIVE BELTS - 3.7L / 4.7L (Continued)

DRIVE BELTS - 5.9L

DIAGNOSIS AND TESTING - ACCESSORY DRIVE BELT

VISUAL DIAGNOSIS

When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib (Fig. 10), are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced (Fig. 10). Also replace the belt if it has excessive wear, frayed cords or severe glazing.

Refer to ACCESSORY DRIVE BELT DIAGNOSIS CHART for further belt diagnosis.

Fig. 8 BELT ROUTING 3.7L / 4.7L

1 - GENERATOR PULLEY 2 - ACCESSORY DRIVE BELT 3 - POWER STEERING PUMP PULLEY 4 - CRANKSHAFT PULLEY 5 - IDLER PULLEY 6 - TENSIONER 7 - A/C COMPRESSOR PULLEY 8 - WATER PUMP PULLEY

Fig. 9 Accessory Drive Belt Wear Indicator–4.7L

Engine

1 - AUTOMATIC TENSIONER ASSEMBLY

Fig. 10 Belt Wear Patterns

1 - NORMAL CRACKS BELT OK 2 - NOT NORMAL CRACKS REPLACE BELT

NOISE DIAGNOSIS

Page 29

DR ACCESSORY DRIVE 7 - 29

DRIVE BELTS - 5.9L (Continued)

ACCESSORY DRIVE BELT DIAGNOSIS CHART

CONDITION POSSIBLE CAUSES CORRECTION

RIB CHUNKING (One or more ribs has separated from belt body)

RIB OR BELT WEAR 1. Pulley misaligned 1. Align pulley(s)

BELT SLIPS 1. Belt slipping because of

1. Foreign objects imbedded in pulley grooves.

2. Installation damage 2. Replace belt

2. Abrasive environment 2. Clean pulley(s). Replace belt if

3. Rusted pulley(s) 3. Clean rust from pulley(s)

4. Sharp or jagged pulley groove tips

5. Belt rubber deteriorated 5. Replace belt

insufficient tension

2. Belt or pulley exposed to substance that has reduced friction (belt dressing, oil, ethylene glycol)

3. Driven component bearing failure (seizure)

4. Belt glazed or hardened from heat and excessive slippage

1. Remove foreign objects from pulley grooves. Replace belt.

necessary

4. Replace pulley. Inspect belt.

1. Inspect/Replace tensioner if necessary

2. Replace belt and clean pulleys

3. Replace faulty component or bearing

4. Replace belt.

LONGITUDAL BELT CRACKING 1. Belt has mistracked from pulley

groove

2. Pulley groove tip has worn away rubber to tensile member

9GROOVE JUMPING9 (Belt does not maintain correct position on pulley)

BELT BROKEN (Note: Identify and correct problem before new belt is installed)

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Pulley(s) not within design tolerance

3. Foreign object(s) in grooves 3. Remove foreign objects from

4. Pulley misalignment 4. Align component

5. Belt cordline is broken 5. Replace belt

1. Incorrect belt tension 1. Replace Inspect/Replace

2. Tensile member damaged during belt installation

3. Severe misalignment 3. Align pulley(s)

4. Bracket, pulley, or bearing failure 4. Replace defective component

1. Replace belt

2. Replace belt

necessary

2. Replace pulley(s)

grooves

tensioner if necessary

2. Replace belt

and belt

Page 30

7 - 30 ACCESSORY DRIVE DR

DRIVE BELTS - 5.9L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

NOISE (Objectionable squeal, squeak, or rumble is heard or felt while drive belt is in operation)

TENSION SHEETING FABRIC FAILURE (Woven fabric on outside, circumference of belt has cracked or separated from body of belt)

CORD EDGE FAILURE (Tensile member exposed at edges of belt or separated from belt body)

1. Incorrect belt tension 1. Inspect/Replace tensioner if necessary

2. Bearing noise 2. Locate and repair

3. Belt misalignment 3. Align belt/pulley(s)

4. Belt to pulley mismatch 4. Install correct belt

5. Driven component induced

vibration

1. Tension sheeting contacting

stationary object

2. Excessive heat causing woven

fabric to age

3. Tension sheeting splice has

fractured

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Belt contacting stationary object 2. Replace belt

3. Pulley(s) out of tolerance 3. Replace pulley

4. Insufficient adhesion between

tensile member and rubber matrix

5. Locate defective driven component and repair

1. Correct rubbing condition

2. Replace belt

3. Replace belt

necessary

4. Replace belt

REMOVAL

NOTE: The belt routing schematics are published from the latest information available at the time of publication. If anything differs between these schematics and the Belt Routing Label, use the schematics on Belt Routing Label.This label is located in the engine compartment.

CAUTION: Do not attempt to check belt tension with a belt tension gauge on vehicles equipped with an automatic belt tensioner. Refer to Automatic Belt Tensioner in this group.

Drive belts on these engines are equipped with a spring loaded automatic belt tensioner (Fig. 11). This belt tensioner will be used on all belt configurations, such as with or without power steering or air conditioning. For more information, (Refer to 7 - COOLING/ACCESSORY DRIVE/BELT TENSIONERS DESCRIPTION).

(1) Attach a socket/wrench to pulley mounting bolt of automatic tensioner (Fig. 11).

(2) Rotate tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.

(3) Remove belt from idler pulley first.

(4) Remove belt from vehicle.

Fig. 11 Belt Tensioner - 5.9L Gas Engines

1 - IDLER PULLEY 2 - TENSIONER 3 - FAN BLADE

Page 31

DR ACCESSORY DRIVE 7 - 31

DRIVE BELTS - 5.9L (Continued)

INSTALLATION

CAUTION: When installing the accessory drive belt, the belt must be routed correctly. If not, engine may overheat due to water pump rotating in wrong direction. Refer to (Fig. 12) (Fig. 13) for correct engine belt routing. The correct belt with correct length must be used.

(1) Position drive belt over all pulleys except idler pulley. This pulley is located between generator and A/C compressor.

(2) Attach a socket/wrench to pulley mounting bolt of automatic tensioner (Fig. 11).

(3) Rotate socket/wrench clockwise. Place belt over idler pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated on all pulleys.

(4) Check belt indexing marks (Refer to 7 - COOLING/ACCESSORY DRIVE/BELT TENSIONERS DESCRIPTION).

Fig. 13 Belt Routing - 5.9L Engines Without A/C

1 - GENERATOR PULLEY 2 - IDLER PULLEY 3 - POWER STEERING PULLEY 4 - CRANKSHAFT PULLEY 5 - WATER PUMP PULLEY 6 - TENSIONER PULLEY

Fig. 12 Belt Routing - 5.9L Engines with A/C

1 - GENERATOR PULLEY 2 - A/C PULLEY 3 - POWER STEERING PULLEY 4 - CRANKSHAFT PULLEY 5 - WATER PUMP PULLEY 6 - TENSIONER PULLEY 7 - IDLER PULLEY

DRIVE BELTS - 5.9L DIESEL

DIAGNOSIS AND TESTING—ACCESSORY DRIVE BELT

VISUAL DIAGNOSIS

When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib (Fig. 14), are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced (Fig. 14). Also replace the belt if it has excessive wear, frayed cords or severe glazing.

Page 32

7 - 32 ACCESSORY DRIVE DR

DRIVE BELTS - 5.9L DIESEL (Continued)

Refer to ACCESSORY DRIVE BELT DIAGNOSIS

CHART for further belt diagnosis.

Fig. 14 Belt Wear Patterns

1 - NORMAL CRACKS BELT OK 2 - NOT NORMAL CRACKS REPLACE BELT

NOISE DIAGNOSIS

ACCESSORY DRIVE BELT DIAGNOSIS CHART

CONDITION POSSIBLE CAUSES CORRECTION

RIB CHUNKING (One or more ribs has separated from belt body)

RIB OR BELT WEAR 1. Pulley misaligned 1. Align pulley(s)

BELT SLIPS 1. Belt slipping because of

1. Foreign objects imbedded in pulley grooves.

2. Installation damage 2. Replace belt

2. Abrasive environment 2. Clean pulley(s). Replace belt if

3. Rusted pulley(s) 3. Clean rust from pulley(s)

4. Sharp or jagged pulley groove tips

5. Belt rubber deteriorated 5. Replace belt

insufficient tension

2. Belt or pulley exposed to substance that has reduced friction (belt dressing, oil, ethylene glycol)

3. Driven component bearing failure (seizure)

4. Belt glazed or hardened from heat and excessive slippage

1. Remove foreign objects from pulley grooves. Replace belt.

necessary

4. Replace pulley. Inspect belt.

1. Inspect/Replace tensioner if necessary

2. Replace belt and clean pulleys

3. Replace faulty component or bearing

4. Replace belt.

Page 33

DR ACCESSORY DRIVE 7 - 33

DRIVE BELTS - 5.9L DIESEL (Continued)

CONDITION POSSIBLE CAUSES CORRECTION

LONGITUDAL BELT CRACKING 1. Belt has mistracked from pulley

groove

2. Pulley groove tip has worn away rubber to tensile member

9GROOVE JUMPING9 (Belt does not maintain correct position on pulley)

BELT BROKEN (Note: Identify and correct problem before new belt is installed)

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Pulley(s) not within design tolerance

3. Foreign object(s) in grooves 3. Remove foreign objects from

4. Pulley misalignment 4. Align component

5. Belt cordline is broken 5. Replace belt

1. Incorrect belt tension 1. Replace Inspect/Replace

2. Tensile member damaged during belt installation

3. Severe misalignment 3. Align pulley(s)

4. Bracket, pulley, or bearing failure 4. Replace defective component

1. Replace belt

2. Replace belt

necessary

2. Replace pulley(s)

grooves

tensioner if necessary

2. Replace belt

and belt

NOISE (Objectional squeal, squeak, or rumble is heard or felt while drive belt is in operation)

TENSION SHEETING FABRIC FAILURE (Woven fabric on outside, circumference of belt has cracked or separated from body of belt)

CORD EDGE FAILURE (Tensile member exposed at edges of belt or separated from belt body)

1. Incorrect belt tension 1. Inspect/Replace tensioner if necessary

2. Bearing noise 2. Locate and repair

3. Belt misalignment 3. Align belt/pulley(s)

4. Belt to pulley mismatch 4. Install correct belt

5. Driven component induced

vibration

1. Tension sheeting contacting

stationary object

2. Excessive heat causing woven

fabric to age

3. Tension sheeting splice has

fractured

1. Incorrect belt tension 1. Inspect/Replace tensioner if

2. Belt contacting stationary object 2. Replace belt

3. Pulley(s) out of tolerance 3. Replace pulley

4. Insufficient adhesion between

tensile member and rubber matrix

5. Locate defective driven component and repair

1. Correct rubbing condition

2. Replace belt

3. Replace belt

necessary

4. Replace belt

Page 34

7 - 34 ACCESSORY DRIVE DR

DRIVE BELTS - 5.9L DIESEL (Continued)

NOTE: The engine speed sensor face is very close to the accessory drive belt. Inspect engine speed sensor and wire harness for damage when accessory drive belt has been replaced due to failure or abnormal conditions.

REMOVAL

CAUTION: Do not attempt to check belt tension with a belt tension gauge on vehicles equipped with an automatic belt tensioner. Refer to Automatic Belt Tensioner in this group.

Drive belts on diesel engines are equipped with a

spring loaded automatic belt tensioner. displays the

tensioner for vehicles without air conditioning.

This belt tensioner will be used on all belt configurations, such as with or without air conditioning. For more information, (Refer to 7 - COOLING/ACCESSORY DRIVE/BELT TENSIONERS - DESCRIPTION).

(1) A 1/2 inch square hole is provided in the automatic belt tensioner. Attach a 1/2 inch drive-long handle ratchet to this hole.

(2) Rotate ratchet and tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.

(3) Remove belt from water pump pulley first.

(4) Remove belt from vehicle.

INSTALLATION

CAUTION: When installing the accessory drive belt, the belt must be routed correctly. If not, engine may

overheat due to water pump rotating in wrong direction. Refer to (Fig. 15) for correct engine belt routing. The correct belt with correct length must be used.

(1) Position drive belt over all pulleys except

water pump pulley.

(2) Attach a 1/2 inch ratchet to tensioner.

(3) Rotate ratchet and belt tensioner clockwise. Place belt over water pump pulley. Let tensioner rotate back into place. Remove ratchet. Be sure belt is properly seated on all pulleys.

Fig. 15 Belt Routing–5.9L Diesel Engine

1 - GENERATOR PULLEY 2 - WATER PUMP PULLEY 3 - IDLER PULLEY 4 - POWER STEERING PUMP PULLEY 5 - RADIATOR FAN PULLEY 6 - CRANKSHAFT PULLEY 7 - AUTOMATIC TENSIONER 8 - A/C COMPRESSOR PUMP PULLEY

Page 35

DR ENGINE 7 - 35

ENGINE

TABLE OF CONTENTS

page page

COOLANT

DESCRIPTION

DESCRIPTION - ENGINE COOLANT .......36

DESCRIPTION - HOAT COOLANT .........37

OPERATION ...........................38

COOLANT RECOVERY CONTAINER-5.9L

DESCRIPTION .........................38

OPERATION ...........................38

REMOVAL .............................38

INSTALLATION .........................38

COOLANT DEGAS CONTAINER-3.7L/4.7L

DESCRIPTION .........................38

OPERATION ...........................38

REMOVAL .............................39

INSTALLATION .........................39

RADIATOR FAN

REMOVAL .............................39

CLEANING ............................40

INSPECTION ..........................40

INSTALLATION .........................40

RADIATOR FAN - 5.9L DIESEL

REMOVAL .............................41

CLEANING ............................41

INSPECTION ..........................41

INSTALLATION .........................41

ENGINE BLOCK HEATER

DESCRIPTION .........................42

OPERATION ...........................42

DIAGNOSIS AND TESTING — ENGINE BLOCK

HEATER ............................42

REMOVAL .............................43

INSTALLATION .........................43

ENGINE BLOCK HEATER - 5.9L DIESEL

DESCRIPTION .........................43

OPERATION ...........................43

REMOVAL .............................43

INSTALLATION .........................44

ENGINE COOLANT TEMPERATURE SENSOR

DESCRIPTION .........................44

OPERATION ...........................44

REMOVAL .............................44

INSTALLATION .........................47

ENGINE COOLANT THERMOSTAT- 5.7L/5.9L

DESCRIPTION .........................47

OPERATION ...........................48

DIAGNOSIS AND TESTING—THERMOSTAT . . . 48

REMOVAL .............................48

INSTALLATION .........................49

ENGINE COOLANT THERMOSTAT - 3.7L/4.7L

DESCRIPTION .........................50

OPERATION ...........................51

DIAGNOSIS AND TESTING—THERMOSTAT . . . 51

REMOVAL .............................51

INSTALLATION .........................51

ENGINE COOLANT THERMOSTAT - 5.9L

DIESEL

DESCRIPTION .........................52

OPERATION ...........................52

DIAGNOSIS AND TESTING—THERMOSTAT . . . 52

REMOVAL .............................53

INSTALLATION .........................53

FAN DRIVE VISCOUS CLUTCH

DESCRIPTION .........................54

OPERATION ...........................54

DIAGNOSIS AND TESTING - VISCOUS FAN

DRIVE ..............................54

FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL

DESCRIPTION .........................55

OPERATION ...........................55

DIAGNOSIS AND TESTING - ELECTRONICLY

CONTOLLED VISCOUS FAN DRIVE .......56

RADIATOR

DESCRIPTION .........................56

OPERATION ...........................56

DIAGNOSIS AND TESTING—RADIATOR

COOLANT FLOW ......................57

REMOVAL .............................57

CLEANING ............................58

INSPECTION ..........................58

INSTALLATION .........................58

RADIATOR - 5.9L DIESEL

DESCRIPTION .........................59

OPERATION ...........................59

DIAGNOSIS AND TESTING—RADIATOR

COOLANT FLOW ......................59

REMOVAL .............................59

CLEANING ............................60

INSPECTION ..........................60

INSTALLATION .........................60

RADIATOR PRESSURE CAP

DESCRIPTION .........................60

OPERATION ...........................61

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING—RADIATOR

CAP-TO-FILLER NECK SEAL.............61

DIAGNOSIS AND TESTING - RADIATOR

CAP................................61

CLEANING ............................62

INSPECTION ..........................62

Page 36

7 - 36 ENGINE DR

WATER PUMP - 5.9L

DESCRIPTION .........................62

OPERATION ...........................62

DIAGNOSIS AND TESTING—WATER PUMP . . . 62

REMOVAL .............................63

CLEANING ............................64

INSPECTION ..........................64

INSTALLATION .........................64

WATER PUMP - 3.7L/4.7L

DESCRIPTION

DESCRIPTION—WATER PUMP ...........64

DESCRIPTION—WATER PUMP BYPASS ....64

OPERATION

OPERATION—WATER PUMP ............64

OPERATION—WATER PUMP BYPASS .....65

REMOVAL .............................65

CLEANING ............................66

INSPECTION ..........................66

INSTALLATION .........................66

WATER PUMP - 5.9L DIESEL

DESCRIPTION .........................67

COOLANT

DESCRIPTION

DESCRIPTION - ENGINE COOLANT

ETHYLENE-GLYCOL MIXTURES

CAUTION: Richer antifreeze mixtures cannot be measured with normal field equipment and can cause problems associated with 100 percent ethylene-glycol.

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only Mopart Antifreeze/Coolant, 5 year/ 100,000Mil;e Formula (ethylene-glycol base coolant with corrosion inhibitors called HOAT, for Hybrid Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain a freeze point of -37°C (-35°F).

The required ethylene-glycol (antifreeze) and water mixture depends upon the climate and vehicle operating conditions. The antifreeze concentration must always be a minimum of 44 percent, year-round in all climates. If percentage is lower than 44 per-

cent, engine parts may be eroded by cavitation, and cooling system components may be severely damaged by corrosion. Maximum protec-

tion against freezing is provided with a 68% antifreeze concentration, which prevents freezing down to

OPERATION ...........................67

DIAGNOSIS AND TESTING—WATER PUMP . . . 67

REMOVAL .............................67

CLEANING ............................67

INSPECTION ..........................68

INSTALLATION .........................68

WATER PUMP INLET TUBE - 5.9L

REMOVAL

REMOVAL - WATER PUMP BYPASS HOSE

WITH AIR CONDITIONING...............68

REMOVAL - WATER PUMP BYPASS HOSE

WITHOUT AIR CONDITIONING ...........69

INSTALLATION

INSTALLATION - WATER PUMP BYPASS

HOSE WITH AIR CONDITIONING .........70

INSTALLATION - WATER PUMP BYPASS

HOSE WITHOUT AIR CONDITIONING ......70

WATER PUMP - 5.7L

REMOVAL .............................70

INSTALLATION .........................71

-67.7° C (-90° F). A higher percentage will freeze at a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because the specific heat of antifreeze is lower than that of water.

Use of 100 percent ethylene-glycol will cause formation of additive deposits in the system, as the corrosion inhibitive additives in ethylene-glycol require the presence of water to dissolve. The deposits act as insulation, causing temperatures to rise to as high as 149° C (300° F). This temperature is hot enough to melt plastic and soften solder. The increased temperature can result in engine detonation. In addition, 100 percent ethylene-glycol freezes at 22° C (-8° F ).

PROPYLENE-GLYCOL MIXTURES

It’s overall effective temperature range is smaller than that of ethylene-glycol. The freeze point of 50/50 propylene-glycol and water is -32° C (-26° F). 5° C higher than ethylene-glycol’s freeze point. The boiling point (protection against summer boil-over) of propylene-glycol is 125° C (257°F)at96.5 kPa (14 psi), compared to 128° C (263° F) for ethylene-glycol. Use of propylene-glycol can result in boil-over or freeze-up on a cooling system designed for ethylene-glycol. Propylene glycol also has poorer heat transfer characteristics than ethylene glycol. This can increase cylinder head temperatures under certain conditions.

Propylene-glycol/ethylene-glycol Mixtures can cause the destabilization of various corrosion inhibitors, causing damage to the various cooling system

Page 37

DR ENGINE 7 - 37

COOLANT (Continued)

components. Also, once ethylene-glycol and propylene-glycol based coolants are mixed in the vehicle, conventional methods of determining freeze point will not be accurate. Both the refractive index and specific gravity differ between ethylene glycol and propylene glycol.

DESCRIPTION - HOAT COOLANT

WARNING: ANTIFREEZE IS AN ETHYLENE-GLYCOL BASE COOLANT AND IS HARMFUL IF SWALLOWED OR INHALED. IF SWALLOWED, DRINK TWO GLASSES OF WATER AND INDUCE VOMITING. IF INHALED, MOVE TO FRESH AIR AREA. SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT STORE IN OPEN OR UNMARKED CONTAINERS. WASH SKIN AND CLOTHING THOROUGHLY AFTER COMING IN CONTACT WITH ETHYLENE-GLYCOL. KEEP OUT OF REACH OF CHILDREN. DISPOSE OF GLYCOL BASE COOLANT PROPERLY, CONTACT YOUR DEALER OR GOVERNMENT AGENCY FOR LOCATION OF COLLECTION CENTER IN YOUR AREA. DO NOT OPEN A COOLING SYSTEM WHEN THE ENGINE IS AT OPERATING TEMPERATURE OR HOT UNDER PRESSURE, PERSONAL INJURY CAN RESULT. AVOID RADIATOR COOLING FAN WHEN ENGINE COMPARTMENT RELATED SERVICE IS PERFORMED, PERSONAL INJURY CAN RESULT.

CAUTION: Use of Propylene-Glycol based coolants is not recommended, as they provide less freeze protection and less corrosion protection.

The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder head area near the exhaust valves and engine block. Then coolant carries the heat to the radiator where the tube/fin radiator can transfer the heat to the air.

The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection. Mopart Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769), or the equivalent ethylene-glycol base coolant with organic corrosion inhibitors (called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% ethylene-glycol and 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

CAUTION: MoparT Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any other type of antifreeze. Mixing of

coolants other than specified (non-HOAT or other HOAT), may result in engine damage that may not be covered under the new vehicle warranty, and decreased corrosion protection.

COOLANT PERFORMANCE

The required ethylene-glycol (antifreeze) and water mixture depends upon climate and vehicle operating conditions. The coolant performance of various mixtures follows:

Pure Water-Water can absorb more heat than a mixture of water and ethylene-glycol. This is for purpose of heat transfer only. Water also freezes at a higher temperature and allows corrosion.

100 percent Ethylene-Glycol-The corrosion inhibiting additives in ethylene-glycol need the presence of water to dissolve. Without water, additives form deposits in system. These act as insulation causing temperature to rise to as high as 149°C (300°F). This temperature is hot enough to melt plastic and soften solder. The increased temperature can result in engine detonation. In addition, 100 percent ethylene-glycol freezes at -22°C (-8°F).

50/50 Ethylene-Glycol and Water-Is the recommended mixture, it provides protection against freezing to -37°C (-34°F). The antifreeze concentration must always be a minimum of 44 percent, yearround in all climates. If percentage is lower, engine parts may be eroded by cavitation. Maximum protection against freezing is provided with a 68 percent antifreeze concentration, which prevents freezing down to -67.7°C (-90°F). A higher percentage will freeze at a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because specific heat of antifreeze is lower than that of water.

CAUTION: Richer antifreeze mixtures cannot be measured with normal field equipment and can cause problems associated with 100 percent ethylene-glycol.

COOLANT SELECTION AND ADDITIVES

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only Mopart Antifreeze/Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with corrosion inhibitors called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

Page 38

7 - 38 ENGINE DR

COOLANT (Continued)

CAUTION: Do not use coolant additives that are claimed to improve engine cooling.

OPERATION

Coolant flows through the engine block absorbing the heat from the engine, then flows to the radiator where the cooling fins in the radiator transfers the heat from the coolant to the atmosphere. During cold weather the ethylene-glycol or propylene-glycol coolant prevents water present in the cooling system from freezing within temperatures indicated by mixture ratio of coolant to water.

COOLANT RECOVERY CONTAINER-5.9L

DESCRIPTION

The coolant reserve/overflow tank is mounted on top of the fan shroud, and is made of high temperature plastic (Fig. 1).

a convenient and safe method for checking coolant level and adjusting level at atmospheric pressure. This is done without removing the radiator pressure cap. The system also provides some reserve coolant to the radiator to cover minor leaks and evaporation or boiling losses.

As the engine cools, a vacuum is formed in the cooling system of both the radiator and engine. Coolant will then be drawn from the coolant tank and returned to a proper level in the radiator.

REMOVAL

(1) Remove recovery hose from radiator.

(2) Remove the coolant container to fan shroud mounting bolt.

(3) Tilt the container backward towards the engine to disengage the mounting pin locking features and lift the container away from the fan shroud (Fig. 1).

INSTALLATION

(1) Align the coolant container mounting pins into the slots on the fan shroud and push the container onto the fan shroud.

(2) Secure the container to the fan shroud with the bolt. Tighten to 8.5N·m (75 in-lbs).

Fig. 1 Coolant Recovery Bottle — 5.9L

1 - SCREW 2 - COOLANT RECOVERY CONTAINER 3 - RADIATOR/RADIATOR CAP 4 - FAN SHROUD

OPERATION

The coolant reserve/overflow system works in conjunction with the radiator pressure cap. It utilizes thermal expansion and contraction of coolant to keep coolant free of trapped air. It provides a volume for expansion and contraction of coolant. It also provides

NOTE: Ensure that the locking feature on the mounting pins has engaged.

(3) Connect the recovery hose to the radiator (Fig.

1).

COOLANT DEGAS CONTAINER-3.7L/4.7L

DESCRIPTION

The coolant degas container is mounted on top of the fan shroud and is made of high temperatyre plastic (Fig. 2).

OPERATION

The coolant degas system works in parallel with the radiator. It is fed through a vent line connected to the top of the radiator inlet tank and returns to the engine/coolant pump via the heater return hoses. This plumbing arrangement, together with the inlet thermostat, provides for constant flow through the degas container whenever the engine is running. The air space in the top of the degas container serves several functions. It provides a volume for the expansion of coolant during engine operation. It provides a space for quick de-aeration of the coolant. Since the container is the highest point in the cooling system, any air trapped in the coolant will quickly be transported to the degas container and be separated out.

Page 39

DR ENGINE 7 - 39

COOLANT DEGAS CONTAINER-3.7L/4.7L (Continued)

INSTALLATION

(1) Align the mounting pins into the slots on the fan shroud and push the container into the fan shroud.

(2) Secure the coolant container to the fan shroud with bolts. Tighten to 8.5 N-m (75 in. lbs).

NOTE: Ensure the locking feature on the mounting pins has engaged.

(3) Connect the supply and return hoses to the container and ensure that the hose clamps are positioned properly.

(4) Refill the cooling system(Refer to 7 - COOLING

- STANDARD PROCEDURE).

RADIATOR FAN

REMOVAL

CAUTION: If the viscous fan drive is replaced

Fig. 2 Coolant Degas Container

1 - SCREWS 2 - COOLANT DEGAS CONTAINER 3 - FAN SHROUD 4 - RADIATOR

The air space also acts as sort of a spring that provides constant system pressurization in conjunction with the radiator cap on top of the container. By returning coolant to the pump side of the inlet thermostat, the degas container also supplies greater pressure to the coolant pump, providing for enhanced coolant flow at high engine speeds.

The degas container also provides a convenient and safe method for checking the coolant level with out removing the radiator pressure cap. The degas container does not require a separate overflow container since it was designed with enough volume to provide a coolant reserve and also protect for any after-boil conditions.

REMOVAL

(1) Drain enough coolant from the system so that the degas container is empty. Refer to Draining Cooling System 3.7L/4.7L Engines in this group

(2) Loosen the clamps securing the supply and return hoses to the container and remove the hoses.

(3) Remove the coolant container to fan shroud mounting bolts.

(4) Tilt the container back towards the engine to disengage the mounting pin locking features and lift the container away from the fan shroud.

because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive malfunction.

(1) Disconnect negative battery cable from battery.

(2) Remove coolant reserve/overflow container from fan shroud and lay aside. Do Not disconnect the hoses or drain coolant from the container.

(3) The thermal viscous fan drive/fan blade assembly is attached (threaded) to the water pump hub shaft (Fig. 4). Remove the fan blade/viscous fan drive assembly from the water pump by turning the mounting nut counterclockwise as viewed from the front. Threads on the viscous fan drive are RIGHT- HAND. A 36 MM Fan Wrench should be used to prevent pulley from rotating (Fig. 3).

(4) Do Not attempt to remove the fan/viscous fan drive assembly from the vehicle at this time.

(5) Do Not unbolt the fan blade assembly (Fig. 4) from viscous fan drive at this time.

(6) Remove the fan shroud-to-radiator mounting bolts.

(7) Pull the lower shroud mounts out of the radiator tank clips.

(8) Remove the fan shroud and fan blade/viscous fan drive assembly as a complete unit from vehicle.

(9) After removing the fan blade/viscous fan drive assembly, do not place the viscous fan drive in a horizontal position. If stored horizontally, silicone

Page 40

7 - 40 ENGINE DR

RADIATOR FAN (Continued)

CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.

CLEANING

Clean the fan blades using a mild soap and water. Do not use an abrasive to clean the blades.

INSPECTION

WARNING: DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN SPECIFICATIONS.

CAUTION: If fan blade assembly is replaced because of mechanical damage, water pump and viscous fan drive should also be inspected. These

Fig. 3 Using Special Tool 6958 Spanner Wrench

1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346 2-FAN

components could have been damaged due to excessive vibration.

(1) Remove fan blade assembly from viscous fan drive unit (six bolts).

(2) Lay fan on a flat surface with leading edge facing down. With tip of blade touching flat surface, replace fan if clearance between opposite blade and surface is greater than 2.0 mm (.090 inch). Rocking motion of opposite blades should not exceed 2.0 mm (.090 inch). Test all blades in this manner.

(3) Inspect fan assembly for cracks, bends, or broken welds. Replace fan if any damage is found.

Fig. 4 Fan Blade/Viscous Fan Drive - Gas Engines -

Typical

1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY

fluid in the viscous fan drive could drain into its bearing assembly and contaminate lubricant.

CAUTION: Do not remove water pump pulley-to-water pump bolts. This pulley is under spring tension.

(10) Remove four bolts securing fan blade assem-

bly to viscous fan drive (Fig. 4).

INSTALLATION

(1) Install fan blade assembly to the viscous fan drive. Tighten the bolts (Fig. 4) to 24 N·m (18 ft. lbs.) torque.

(2) Position the fan shroud and the fan blade/viscous fan drive assembly to the vehicle as a complete unit.

(3) Install the fan shroud.

(4) Install the fan blade/viscous fan drive assembly to the water pump shaft (Fig. 4).

(5) Install the coolant reserve/overflow container to the fan shroud.

(6) Connect the negative battery cable.

NOTE: Viscous Fan Drive Fluid Pump Out Requirement: After installing a new viscous fan drive, bring the engine speed up to approximately 2000 rpm and hold for approximately two minutes. This will ensure proper fluid distribution within the drive.

Page 41

DR ENGINE 7 - 41

RADIATOR FAN - 5.9L DIESEL

REMOVAL

CAUTION: If the electronically controlled viscous fan drive is replaced because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect wiring harness and connectors for damage.

(1) Disconnect the battery negative cables. (2) Remove the fan shroud lower half. by unsnap-

ping the fastening tabs.

CAUTION: Do not remove the fan pulley bolts. This pulley is under spring tension.

(3) Disconnect electrical connector.

(4) The electronically controlled viscous fan drive/ fan blade assembly is attached (threaded) to the fan hub shaft (Fig. 5). Remove the fan blade/fan drive assembly from fan pulley by turning the mounting nut counterclockwise (as viewed from front). Threads on the viscous fan drive are RIGHT-HAND. A Snap-On 36 MM Fan Wrench (number SP346 from Snap-On Cummins Diesel Tool Set number 2017DSP) can be used. Place a bar or screwdriver between the fan pulley bolts to prevent pulley from rotating.

(5) Remove the fan shroud and the fan blade/viscous drive as an assembly from vehicle from under the vehicle.

(6) Remove fan blade-to-viscous fan drive mounting bolts.

(7) Inspect the fan for cracks, loose or bent fan blades.

CAUTION: Some engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. Installation of the wrong fan or viscous fan drive can result in engine overheating.

1 - ELECTRICAL CONNECTOR 2 - VISCOUS FAN DRIVE 3 - FAN BLADE 4 - BOLT 5 - FAN DRIVE

CAUTION: If fan blade assembly is replaced because of mechanical damage, water pump and viscous fan drive should also be inspected. These components could have been damaged due to excessive vibration.

(1) Remove fan blade assembly from viscous fan

drive unit (six bolts).

(3) Inspect fan assembly for cracks, bends, or broken welds. Replace fan if any damage is found.

Fig. 5 Fan Blade/Viscous Fan Drive

CLEANING

Clean the fan blades using a mild soap and water.

Do not use an abrasive to clean the blades.

INSPECTION

WARNING: DO NOT ATTEMPT TO BEND OR STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN SPECIFICATIONS.

INSTALLATION

(1) Install fan blade assembly to electrically controlled viscous fan drive. Tighten mounting bolts to 23 N·m (17 ft. lbs.) torque.

(2) Position the fan blade/viscous fan drive to the vehicle as an assembly.

(3) Install viscous fan drive assembly on fan hub shaft (Fig. 5). Tighten mounting nut to 33 N·m (24 ft. lbs.) torque.

(4) Connect electrical connector.

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7 - 42 ENGINE DR

RADIATOR FAN - 5.9L DIESEL (Continued)

(5) Install the lower fan shroud into position and

verify the locking tabs have seated.

(6) Connect the battery negative cables.

ENGINE BLOCK HEATER

DESCRIPTION

WARNING: DO NOT OPERATE ENGINE UNLESS BLOCK HEATER CORD HAS BEEN DISCONNECTED FROM POWER SOURCE AND SECURED IN PLACE. THE POWER CORD MUST BE SECURED IN ITS RETAINING CLIPS AND ROUTED AWAY FROM EXHAUST MANIFOLDS AND MOVING PARTS.

An optional engine block heater is available with all models. The heater is equipped with a power cord. The cord is attached to an engine compartment component with tie-straps. The heater warms the engine providing easier engine starting and faster warm-up in low temperatures. The heater is mounted in a core hole of the engine cylinder block in place of a freeze plug with the heating element immersed in engine coolant. The 5.9L gas powered engine has the block heater located on the right side of engine next to the oil filter (Fig. 6). The 3.7L/4.7L gas powered engines have the block heater located to the rear on the right side of the engine (Fig. 7).

1 - FREEZE PLUG HOLE 2 - BLOCK HEATER 3 - SCREW 4 - POWER CORD (120V AC) 5 - HEATING COIL 6 - OIL FILTER

Fig. 6 Engine Block Heater - 5.9L

OPERATION

The heater warms the engine coolant providing easier engine starting and faster warm-up in low temperatures. Connecting the power cord to a grounded 110-120 volt AC electrical outlet with a grounded three wire extension cord provides the electricity needed to heat the element.

DIAGNOSIS AND TESTING — ENGINE BLOCK HEATER

If the unit does not operate, possible causes can be either the power cord or the heater element. Test the power cord for continuity with a 110-volt voltmeter or 110-volt test light. Test heater element continuity with an ohmmeter or a 12-volt test light.

CAUTION: To prevent damage, the power cord must be secured in it’s retainer clips and away from any components that may cause abrasion or damage, such as linkages, exhaust components, etc.

Fig. 7 Engine Block Heater - 3.7L/4.7L

1 - ENGINE BLOCK HEATER

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DR ENGINE 7 - 43

ENGINE BLOCK HEATER (Continued)

REMOVAL

(1) Disconnect the battery negative cable.

(2) Drain the coolant (Refer to 7 - COOLING STANDARD PROCEDURE).

(3) Remove the power cord from the heater by unplugging (Fig. 8).

(4) Loosen (but do not completely remove) the screw at center of block heater (Fig. 8).

(5) Remove the block heater by carefully prying from side-to-side. Note the direction of the heating element coil (up or down). The element coil must be installed correctly to prevent damage.

ENGINE BLOCK HEATER - 5.9L DIESEL

DESCRIPTION

An optional engine block heater is available on all models. The heater is equipped with a power cord. The heater is mounted in a threaded hole of the engine cylinder block with the heating element immersed in engine coolant. The cord is attached to an engine compartment component with tie-straps.

The 5.9L diesel engine has the block heater located on the right side of the engine below the exhaust manifold next to the oil cooler (Fig. 9).

Fig. 8 Engine Block Heater

1 - FREEZE PLUG HOLE 2 - BLOCK HEATER 3 - SCREW 4 - POWER CORD (120V AC) 5 - HEATING COIL 6 - OIL FILTER

INSTALLATION

(1) Clean and inspect the block heater hole. (2) Install the new O-ring seal(s) to heater. (3) Insert the block heater into cylinder block and

position the element properly.

(4) With the heater fully seated, tighten center

screw to 2 N·m (17 in. lbs.).

(5) Fill the cooling system with the recommended coolant. (Refer to 7 - COOLING - STANDARD PROCEDURE).

(6) Start and warm the engine.

(7) Check the block heater for leaks.

Fig. 9 Engine Block Heater–5.9L Diesel Engine

1 - BLOCK HEATER

OPERATION

REMOVAL

(1) Disconnect the battery negative cables.

(2) Drain coolant from radiator and cylinder block (Refer to 7 - COOLING - STANDARD PROCEDURE).

(3) Unscrew the power cord retaining cap and disconnect cord from heater element.

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ENGINE BLOCK HEATER - 5.9L DIESEL (Continued)

(4) Using a suitable size socket, loosen and remove

the block heater element (Fig. 10).

Fig. 10 Block Heater-Diesel Engine

1 - BLOCK HEATER

INSTALLATION

(1) Clean and inspect the threads in the cylinder

block.

(2) Coat heater element threads with Mopart

Thread Sealer with Teflon.

(3) Screw block heater into cylinder block and

tighten to 43 N·m (32 ft. lbs.).

(4) Connect block heater cord and tighten retain-

ing cap.

(5) Fill cooling system with recommended coolant (Refer to 7 - COOLING - STANDARD PROCEDURE).

(6) Start and warm the engine.

(7) Check block heater for leaks.

ENGINE COOLANT TEMPERATURE SENSOR

When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer airfuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached.

The PCM uses inputs from the ECT sensor for the following calculations:

• for engine coolant temperature gauge operation

through CCD or PCI (J1850) communications

• Injector pulse-width

• Spark-advance curves

• ASD relay shut-down times

• Idle Air Control (IAC) motor key-on steps

• Pulse-width prime-shot during cranking

• O2 sensor closed loop times

• Purge solenoid on/off times

• EGR solenoid on/off times (if equipped)

• Leak Detection Pump operation (if equipped)

• Radiator fan relay on/off times (if equipped)

• Target idle speed

REMOVAL

3.7L V-6

The Engine Coolant Temperature (ECT) sensor on the 3.7L engine is installed into a water jacket at front of intake manifold near rear of generator (Fig.

11).

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR.

(1) Partially drain the cooling system.

(2) Disconnect the electrical connector from the sensor.

(3) Remove the sensor from the intake manifold.

4.7L V-8

DESCRIPTION

The Engine Coolant Temperature (ECT) sensor is used to sense engine coolant temperature. The sensor protrudes into an engine water jacket.

The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases.

OPERATION

At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return).

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE ENGINE COOLANT TEMPERATURE (ECT) SENSOR.

The Engine Coolant Temperature (ECT) sensor on the 4.7L V-8 engine is located near the front of the intake manifold (Fig. 12).

(1) Partially drain the cooling system. Refer to 7, COOLING.

(2) Disconnect the electrical connector from the ECT sensor.

(3) Remove the sensor from the intake manifold.

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ENGINE COOLANT TEMPERATURE SENSOR (Continued)

compressor (Fig. 13). It is installed into a water jacket at the front of the cylinder block (Fig. 14).

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR.

(1) Partially drain the cooling system.

(2) Remove fan belt. Refer to Accessory Drive in Cooling section.

(3) Carefully unbolt air conditioning compressor from front of engine. Do not disconnect any A/C hoses from compressor. Temporarily support compressor to gain access to ECT sensor. Refer to Heating and Air Conditioning section for information.

(4) Disconnect electrical connector from sensor (Fig. 14).

(5) Remove sensor from cylinder block.

Fig. 11 MAP SENSOR / ECT SENSOR - 3.7L V-6

1 - MOUNTING SCREWS 2 - MAP SENSOR 3 - ECT SENSOR 4 - FRONT OF INTAKE MANIFOLD

Fig. 12 ECT SENSOR - 4.7L V-8

1 - ECT SENSOR 2 - MOUNTING BOLTS (2) 3 - MAP SENSOR 4 - INTAKE MANIFOLD

5.7L V-8

The Engine Coolant Temperature (ECT) sensor on

the 5.7L engine is located under the air conditioning

Fig. 13 ECT LOCATION - 5.7L V-8

1 - TOP OF AIR CONDITIONING COMPRESSOR 2 - ECT SENSOR LOCATION

5.9L Diesel

The Engine Coolant Temperature (ECT) sensor on the 5.9L diesel engine is located near the thermostat housing (Fig. 15).

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR.

(1) Partially drain the cooling system.

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ENGINE COOLANT TEMPERATURE SENSOR (Continued)

5.9L V-8 Gas

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR. REFER TO GROUP 7, COOLING.

(1) Partially drain the cooling system. Refer to 7, COOLING.

(2) Disconnect the electrical connector from the sensor (Fig. 16).

(3) Engines with air conditioning: When removing the connector from the sensor, do not pull directly on the wiring harness. The connector is snapped onto the sensor. It is not equipped with a lock type tab.

(4) Remove the sensor from the intake manifold.

Fig. 14 ECT REMOVE / INSTALL 5.7L V-8

1 - FRONT OF INTAKE MANIFOLD 2 - ELECTRICAL CONNECTOR 3 - ECT SENSOR

(2) Disconnect the electrical connector from the

sensor.

(3) Remove the sensor from the cylinder head.

Fig. 16 ECT SENSOR - 5.9L V-8

1 - GENERATOR 2 - A/C COMPRESSOR 3 - ENGINE COOLANT TEMPERATURE SENSOR 4 - ELEC. CONN.

8.0L V-10

The Engine Coolant Temperature (ECT) sensor on the 8.0L V-10 engine is threaded into the thermostat housing (Fig. 17).

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR.

Fig. 15 ECT LOCATION - 5.9L DIESEL

1 - THERMOSTAT HOUSING 2 - ELECTRICAL CONNECTOR 3 - ECT SENSOR

(1) Partially drain the cooling system.

(2) Disconnect the electrical connector from the sensor.

(3) Remove the sensor from the cylinder head.

Page 47

DR ENGINE 7 - 47

ENGINE COOLANT TEMPERATURE SENSOR (Continued)

(5) Replace any lost engine coolant. Refer to 7, COOLING.

5.9L Diesel

(1) Apply thread sealant to sensor threads.

(2) Install sensor to engine.

(3) Tighten sensor to 18 N·m (13 ft. lbs.) torque.

(4) Connect electrical connector to sensor.

(5) Replace any lost engine coolant. Refer to 7, COOLING.

5.9L V-8 Gas

(1) Apply thread sealant to sensor threads.

(2) Install sensor to engine.

(3) Tighten sensor to 6–8 N·m (55–75 in. lbs.) torque.

(4) Connect electrical connector to sensor. The sensor connector is symmetrical (not indexed). It can be connected to sensor in either direction.

(5) Refill cooling system. Refer to 7, COOLING.

Fig. 17 ECT SENSOR - 8.0L V-10

1 - ENGINE COOLANT TEMP. SENSOR (FOR PCM) 2 - HEATER SUPPLY FITTING 3 - BOLTS (6) 4 - HOUSING WITH INTEGRAL SEAL 5 - THERMOSTAT 6 - RUBBER LIP SEAL 7 - TEMP. GAUGE SENDING UNIT

INSTALLATION

3.7L V-6

(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor. (5) Replace any lost engine coolant. Refer to 7,

COOLING.

4.7L V-8

COOLING.

5.7L V-8

(1) Apply thread sealant to sensor threads. (2) Install sensor to engine. (3) Tighten sensor to 11 N·m (8 ft. lbs.) torque. (4) Connect electrical connector to sensor.

8.0L V-10

(1) Apply thread sealant to sensor threads.

(2) Install sensor to engine.

(3) Tighten sensor to 11 N·m (8 ft. lbs.) torque.

(4) Connect electrical connector to sensor.

(5) Replace any lost engine coolant. Refer to 7, COOLING.

ENGINE COOLANT THERMOSTAT- 5.7L/5.9L

DESCRIPTION

CAUTION: Do not operate an engine without a thermostat, except for servicing or testing.

The thermostat on the 5.7L and 5.9L gas powered engine is located beneath the thermostat housing at the front of the intake manifold (Fig. 18).

The thermostat is a wax pellet driven, reverse poppet choke type.

Coolant leakage into the pellet container will cause the thermostat to fail in the open position. Thermostats very rarely stick. Do not attempt to free a thermostat with a prying device.

The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing. Operating without a thermostat causes longer engine warmup time, unreliable warmup performance, increased exhaust emissions and crankcase condensation that can result in sludge formation.

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7 - 48 ENGINE DR

ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)

REMOVAL

WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE COOLING SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.

Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

If the thermostat is being replaced, be sure that the replacement is the specified thermostat for the vehicle model and engine type.

Factory installed thermostat housings on 5.9L engine is installed on a gasket with an anti-stick coating. This will aid in gasket removal and clean-up.

(1) Disconnect the negative battery cable.

(2) Drain the cooling system until the coolant level is below the thermostat (Refer to 7 - COOLING STANDARD PROCEDURE).

(3) Air Conditioned vehicles: Remove the support

Fig. 18 Thermostat - 5.7L/5.9L Gas Powered

Engines

1 - THERMOSTAT HOUSING 2 - GASKET 3 - INTAKE MANIFOLD 4 - THERMOSTAT 5 - MACHINED GROOVE

bracket (generator mounting bracket-to-intake manifold) located near the rear of the generator (Fig. 19).

OPERATION

The wax pellet is located in a sealed container at the spring end of the thermostat. When heated, the pellet expands, overcoming closing spring tension and water pump pressure to force the valve to open.

DIAGNOSIS AND TESTING—THERMOSTAT

ON-BOARD DIAGNOSTICS

All gasoline powered models are equipped with On-Board Diagnostics for certain cooling system components. Refer to On-Board Diagnostics (OBD) in the Diagnosis section of this group for additional information. If the powertrain control module (PCM) detects low engine coolant temperature, it will record a Diagnostic Trouble Code (DTC) in the PCM memory. Do not change a thermostat for lack of heat as indicated by the instrument panel gauge or by poor heater performance unless a DTC is present. Refer to the Diagnosis section of this group for other probable causes.

The DTC can also be accessed through the DRBIIIt scan tool. Refer to the appropriate Powertrain Diagnostic Procedures information for diagnostic information and operation of the DRBIIIt scan tool.

Fig. 19 Generator Support Bracket – 5.9L Engine

1 - IDLER PULLEY BUSHING 2 - A/C AND/OR GENERATOR MOUNTING BRACKET 3 - IDLER PULLEY 4 - SCREW AND WASHER

NOTE: On air conditioning equipped vehicles, the generator must be partially removed.

(4) Remove the accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL) (Fig. 20).

(5) Remove the generator mounting bolts. Do not remove any of the wiring at the generator. If equipped with 4WD, unplug the 4WD indicator lamp wiring harness (located near rear of generator).

(6) Remove the generator. Position the generator to gain access for the thermostat gasket removal.

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ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)

Fig. 21 SPRING CLAMP SIZE LOCATION

1 - SPRING CLAMP SIZE LOCATION

Fig. 20 Automatic Belt Tensioner – 5.9L Engines

1 - IDLER PULLEY 2 - TENSIONER 3 - FAN BLADE

WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.

CAUTION: A number or letter is stamped into the tongue of the constant tension clamps (Fig. 21). If replacement is necessary, use only an original equipment clamp with a matching number, letter and width.

(7) Remove the radiator upper hose clamp and

upper hose at the thermostat housing.

(8) Position the wiring harness (behind thermostat

housing) to gain access to the thermostat housing.

(9) Remove the thermostat housing mounting bolts, thermostat housing, gasket and thermostat (Fig. 22). Discard old gasket.

INSTALLATION

(1) Clean the mating areas of the intake manifold and thermostat housing.

(2) Install the thermostat (spring side down) into the recessed machined groove on the intake manifold (Fig. 22).

(3) Install the gasket on the intake manifold and over the thermostat (Fig. 22).

Fig. 22 Thermostat – 5.9L Engines

1 - THERMOSTAT HOUSING 2 - GASKET 3 - INTAKE MANIFOLD 4 - THERMOSTAT 5 - MACHINED GROOVE

(4) Position the thermostat housing to the intake manifold. Note: The word FRONT stamped on housing (Fig. 23). For adequate clearance, this must be placed towards the front of the vehicle. The housing is slightly angled forward after the installation to the intake manifold.

(5) Install the housing-to-intake manifold bolts. Tighten the bolts to 23 N·m (200 in. lbs.).

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ENGINE COOLANT THERMOSTAT- 5.7L/5.9L (Continued)

Fig. 23 Thermostat Position—5.9L Engines

(6) Install the radiator upper hose to the thermo-

stat housing.

CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in wrong direction. Refer to (Fig. 24) for the correct 5.9L engine belt routing. The correct belt with correct length must be used.

(7) Air Conditioned vehicles; Install the generator.

Tighten the bolts to 41 N·m (30 ft. lbs.).

(8) Install the support bracket (generator mounting bracket-to-intake manifold). (Fig. 19). Tighten the bolts to 54 N·m (40 ft. lbs.).

(9) Install the accessory drive belt (Fig. 20)(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

(10) Fill the cooling system (Refer to 7 - COOLING

- STANDARD PROCEDURE).

(11) Connect battery negative cable.

(12) Start and warm the engine. Check for leaks.

Fig. 24 Belt Routing – 5.9L Engines

1 - IDLER PULLEY 2 - GENERATOR PULLEY 3 - A/C COMPRESSOR PULLEY 4 - IF W/OUT A/C 5 - POWER STEERING PUMP PULLEY 6 - WATER PUMP PULLEY 7 - CRANKSHAFT PULLEY 8 - AUTOMATIC TENSIONER

ENGINE COOLANT THERMOSTAT - 3.7L/4.7L

DESCRIPTION

CAUTION: Do not operate the engine without a thermostat, except for servicing or testing.

A pellet-type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator. On all engines the thermostat is closed below 195°F (90°C). Above this temperature, coolant is allowed to flow to the radiator. This provides quick engine warm up and overall temperature control. On the 3.7L4.7L engine the thermostat is designed to block the flow of the coolant bypass journal by 50% instead of completely blocking the flow. This design controls coolant temperature more accurately (Fig. 25).

The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing. Operating without a thermostat causes other problems. These are: longer engine warmup time, unreliable warmup performance, increased exhaust

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ENGINE COOLANT THERMOSTAT - 3.7L/4.7L (Continued)

emissions and crankcase condensation. This condensation can result in sludge formation.

Fig. 25 Thermostat Cross Section View 3.7L/4.7L

1 - FROM HEATERAND DEGAS CONTAINER 2 - FROM RADIATOR 3 - TO WATER PUMP 4 - ENGINE BYPASS 5 - THERMOSTAT

OPERATION

the Diagnosis section of this group for other probable causes.

The DTC can also be accessed through the DRBIIIt scan tool. Refer to the appropriate Powertrain Diagnostic Procedures information for diagnostic information and operation of the DRBIIIt scan tool.

REMOVAL

WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE COOLING SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.

Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

If the thermostat is being replaced, be sure that the replacement is the specified thermostat for the vehicle model and engine type.

(1) Disconnect the negative battery cable.

(2) Drain the cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).

(3) Raise and support the vehicle.

(4) Remove the splash shield.

(5) Remove the lower radiator hose clamp and the lower radiator hose at the thermostat housing.

(6) Remove the thermostat housing mounting bolts, thermostat housing and thermostat (Fig. 26).

INSTALLATION

(1) Clean the mating areas of the timing chain cover and the thermostat housing.

(2) Install the thermostat (spring side down) into the recessed machined groove on the timing chain cover (Fig. 26).

(3) Position the thermostat housing on the timing chain cover.

(4) Install the housing-to-timing chain cover bolts. Tighten the bolts to 13 N·m (112 in. lbs.).

DIAGNOSIS AND TESTING—THERMOSTAT

ON-BOARD DIAGNOSTICS

CAUTION: The housing must be tightened evenly and the thermostat must be centered into the recessed groove in the timimg chain cover. If not, it may result in a cracked housing, damaged timing chain cover threads or coolant leaks.

(5) Install the lower radiator hose on the thermo-

stat housing.

(6) Install the splash shield. (7) Lower the vehicle. (8) Fill the cooling system (Refer to 7 - COOLING

- STANDARD PROCEDURE). (9) Connect negative battery cable. (10) Start and warm the engine. Check for leaks.

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7 - 52 ENGINE DR

ENGINE COOLANT THERMOSTAT - 3.7L/4.7L (Continued)

Fig. 26 Thermostat and Thermostat Housing 3.7L/4.7L

1 - THERMOSTAT HOUSING 2 - THERMOSTAT LOCATION

ENGINE COOLANT THERMOSTAT - 5.9L DIESEL

DESCRIPTION

CAUTION: Do not operate an engine without a thermostat, except for servicing or testing. An engine with the thermostat removed will operate in the radiator bypass mode, causing an overheat condition.

The thermostat of the 5.9L diesel engine is located in the front of the cylinder head, underneath the thermostat housing (Fig. 27).

3 - THERMOSTATAND GASKET 4 - TIMING CHAIN COVER

OPERATION

DIAGNOSIS AND TESTING—THERMOSTAT

The cooling system used with the diesel engine provides the extra coolant capacity and extra cooling

Fig. 27 Thermostat–5.9L Diesel-Typical

1 - THERMOSTAT HOUSING 2 - CYLINDER HEAD 3 - THERMOSTAT

protection needed for higher GVWR (Gross Vehicle Weight Rating) and GCWR (Gross Combined Weight Rating) vehicles.

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DR ENGINE 7 - 53

ENGINE COOLANT THERMOSTAT - 5.9L DIESEL (Continued)

This system capacity will not effect warm up or cold weather operating characteristics if the thermostat is operating properly. This is because coolant will be held in the engine until it reaches the thermostat “set” temperature.

Diesel engines, due to their inherent efficiency are slower to warm up than gasoline powered engines, and will operate at lower temperatures when the vehicle is unloaded. Because of this, lower temperature gauge readings for diesel versus gasoline engines may, at times be normal.

Typically, complaints of low engine coolant temperature are observed as low heater output when combined with cool or cold outside temperatures.

To help promote faster engine warm-up, the electric engine block heater must be used with cool or cold outside temperatures. This will help keep the engine coolant warm when the vehicle is parked. Use the block heater if the outside temperature is below 4°C (40°F). Do not use the block heater if the

outside temperature is above 4°C (40°F).

A “Cold Weather Cover” is available from the parts department through the Mopar Accessories product line. This accessory cover is designed to block airflow entering the radiator and engine compartment to promote faster engine warm-up. It attaches to the front of the vehicle at the grill opening. The cover is

to be used with cool or cold temperatures only. If used with high outside temperatures, serious engine damage could result. Refer to the litera-

ture supplied with the cover for additional information.

(1) To determine if the thermostat is defective, it must be removed from the vehicle (Refer to 7 COOLING/ENGINE/ENGINE COOLANT THERMOSTAT - REMOVAL).

(2) After the thermostat has been removed, examine the thermostat and inside of thermostat housing for contaminants. If contaminants are found, the thermostat may already be in a “stuck open” position. Flush the cooling system before replacing thermostat (Refer to 7 - COOLING - STANDARD PROCEDURE).

(3) Place the thermostat into a container filled with water.

(4) Place the container on a hot plate or other suitable heating device.

(5) Place a commercially available radiator thermometer into the water.

(6) Apply heat to the water while observing the thermostat and thermometer.

(7) The thermostat will begin to open at 85.5 —

89.4°C. (186 —193°F ). If the valve starts to move before this temperature is reached, it is opening too early. Replace thermostat. The thermostat should be fully open (valve will stop moving) at 97°C (207°F). If

the valve is still moving when the water temperature reaches 97°C (207°F), it is opening too late. Replace thermostat. If the valve refuses to move at any time, replace thermostat.

REMOVAL

WARNING: DO NOT LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.

Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

(1) Disconnect the battery negative cables.

(2) Drain cooling system until coolant level is below thermostat (Refer to 7 - COOLING - STANDARD PROCEDURE).

WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER

6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20) MAY BE USED FOR LARGER CLAMPS. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with a matching number or letter.

(3) Remove radiator hose clamp and hose from thermostat housing.

(4) Remove the three (3) water outlet-to-cylinder head bolts and remove the water outlet connector (Fig. 28).

(5) Clean the mating surfaces of the water outlet connector and clean the thermostat seat groove at the top of the thermostat housing (Fig. 28).

INSTALLATION

(1) Inspect thermostat seal for cuts or nicks. Replace if damaged.

(2) Install the thermostat into the groove in the top of the cylinder head (Fig. 28).

(3) Install the thermostat housing and bolts. Tighten the bolts to 10 N·m (88 in. lbs.) torque.

(4) Install the radiator upper hose and clamp.

(5) Fill the cooling system with coolant (Refer to 7

- COOLING - STANDARD PROCEDURE).

(6) Connect the battery negative cables.

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7 - 54 ENGINE DR

ENGINE COOLANT THERMOSTAT - 5.9L DIESEL (Continued)

Fig. 29 Viscous Fan

1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY

Fig. 28 Thermostat Removal/Installation

1 - THERMOSTAT HOUSING 2 - CYLINDER HEAD 3 - THERMOSTAT

(7) Start the engine and check for coolant leaks.

Run engine to check for proper thermostat operation.

FAN DRIVE VISCOUS CLUTCH

DESCRIPTION

The thermal viscous fan drive (Fig. 29) is a silicone-fluid- filled coupling used to connect the fan blades to the water pump shaft. The coupling allows the fan to be driven in a normal manner. This is done at low engine speeds while limiting the top speed of the fan to a predetermined maximum level at higher engine speeds.

OPERATION

A thermostatic bimetallic spring coil is located on the front face of the viscous fan drive unit (a typical viscous unit is shown in (Fig. 30). This spring coil reacts to the temperature of the radiator discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed.

Only when sufficient heat is present, will the viscous fan drive engage. This is when the air flowing through the radiator core causes a reaction to the bimetallic coil. It then increases fan speed to provide the necessary additional engine cooling.

Once the engine has cooled, the radiator discharge temperature will drop. The bimetallic coil again reacts and the fan speed is reduced to the previous disengaged speed.

Fig. 30 Viscous Fan Drive—Typical

1 - VISCOUS FAN DRIVE 2 - THERMOSTATIC SPRING 3 - MOUNTING NUT TO WATER PUMP HUB

DIAGNOSIS AND TESTING - VISCOUS FAN DRIVE

NOISE

NOTE: It is normal for fan noise to be louder (roaring) when:

• The underhood temperature is above the engage-

ment point for the viscous drive coupling. This may

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DR ENGINE 7 - 55

FAN DRIVE VISCOUS CLUTCH (Continued)

occur when ambient (outside air temperature) is very high.

• Engine loads and temperatures are high such as

when towing a trailer.

• Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15 seconds to one minute after engine start-up on a cold engine.

LEAKS

Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.

VISCOUS DRIVE

If the fan assembly free-wheels without drag (the fan blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine is cool.

For the following test, the cooling system must be in good condition. It also will ensure against excessively high coolant temperature.

WARNING: BE SURE THAT THERE IS ADEQUATE FAN BLADE CLEARANCE BEFORE DRILLING.

• 3.7L Manual/4.7L Automatic/5.9L — 85° to 91° C

(185° to 195° F)

• 4.7L Manual — 74° to 79° C (165° to 175° F)

• Engagement is distinguishable by a definite

increase in fan flow noise (roaring). The timing light also will indicate an increase in the speed of the fan.

(7) When viscous drive engagement is verified, remove the plastic sheet. Fan drive disengagement should start to occur at or between:

• 3.7L Automatic — 76°C to 81°C (168° F to 178°

• 3.7L Manual/4.7L Auto/ 5.9L — 67°C to 73°C

(153° F to 163° F)

• 4.7L Manual — 56°C to 62°C (133° F to 143° F)

• 8.0L engine — 88° to 96° C (190° to 205° F) A

definite decrease of fan flow noise (roaring) should be noticed. If not, replace the defective viscous fan drive unit.

(1) Drill a 3.18-mm (1/8-in) diameter hole in the

top center of the fan shroud.

(2) Obtain a dial thermometer with an 8 inch stem (or equivalent). It should have a range of -18°-to105°C (0°-to-220° F). Insert thermometer through the hole in the shroud. Be sure that there is adequate clearance from the fan blades.

(3) Connect a tachometer and an engine ignition timing light. The timing light is to be used as a strobe light. This step cannot be used on the diesel engine.

(4) Block the air flow through the radiator. Secure a sheet of plastic in front of the radiator. Use tape at the top to secure the plastic and be sure that the air flow is blocked.

(5) Be sure that the air conditioner (if equipped) is turned off.

WARNING: USE EXTREME CAUTION WHEN THE ENGINE IS OPERATING. DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

(6) Start the engine and operate at 2400 rpm. Within ten minutes the air temperature (indicated on the dial thermometer) should be up to 88° C (190° F). Fan drive engagement should start to occur at/between:

• 3.7L Automatic — 93° C - 99°C (200° F - 210° F)

CAUTION: If the viscous fan drive is replaced because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive malfunction.

FAN DRIVE VISCOUS CLUTCH

- 5.9L DIESEL

DESCRIPTION

The electronically controlled thermal viscous fan drive (Fig. 31) is attached to the fan drive pulley mounted to the engine. The coupling allows the fan to be driven in a normal manner. The fan speed is controlled by the electronic control module.

OPERATION

The Engine Control Module (ECM) controls the level of engagment of the electronically controlled viscous fan clutch by monitoring coolant temperature, intake manifold temperature, and air conditioning status. Based on cooling requirements, the ECM sends a signal to the viscous fan clutch to increase or decrease the fan speed.

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7 - 56 ENGINE DR

FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL (Continued)

ELECTRONICALLY CONTROLLED VISCOUS DRIVE

If the fan assembly free-wheels without drag (the fan blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine is cool.

For the following test, the cooling system must be in good condition. It also will ensure against excessively high coolant temperature.

The Electronic Viscous Fan drive can be tested using the DRB III scan tool.

(1) Set the parking brake and verify the transmission is in park or neutral.

(2) Stat and allow engine to reach normal operating termeratures.

(3) With engine idling, connect the DRB III and select appropraite model year and engine option.

(4) Lacate and select actuator tests, then select PWM Viscous Fan.

(5) Monitor fan speed and duty cycle; verify that the fan speed increments are proportional to the duty cycle precentage during the actuation event.

Fig. 31 Fan Blade/Viscous Fan Drive

1 - ELECTRICAL CONNECTOR 2 - VISCOUS FAN DRIVE 3 - FAN BLADE 4 - BOLT 5 - FAN DRIVE

Fan speed is monitored by the ECM. A lack of fan speed will set a DTC. Circuit concerns will also set fan clutch DTC’s.

Fan speed and duty cycle percent can be monitored with the DRB III..

DIAGNOSIS AND TESTING - ELECTRONICLY CONTOLLED VISCOUS FAN DRIVE

NOISE

NOTE: It is normal for fan noise to be louder (roaring) when:

• Fan duty cycle high. This may occur when ambi-

ent (outside air temperature) is very high.

• Engine loads and temperatures are high such as

when towing a trailer.

LEAKS

Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.

RADIATOR

DESCRIPTION

The radiator is a aluminum cross-flow design with horizontal tubes through the radiator core and vertical plastic side tanks (Fig. 32).

This radiator does not contain an internal transmission oil cooler

OPERATION

The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radiator core to cool the engine.

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DR ENGINE 7 - 57

RADIATOR (Continued)

WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM THE COOLANT CAN OCCUR.

(2) Drain the cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with a matching number or letter and the correct width.

Fig. 32 Radiator — Typical

1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT

DIAGNOSIS AND TESTING—RADIATOR COOLANT FLOW

Use the following procedure to determine if coolant

is flowing through the cooling system.

(1) Idle engine until operating temperature is reached. If the upper radiator hose is warm to the touch, the thermostat is opening and coolant is flowing to the radiator.

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. USING A RAG TO COVER THE RADIATOR PRESSURE CAP, OPEN RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS WILL ALLOW ANY BUILT-UP PRESSURE TO VENT TO THE RESERVE/OVERFLOW TANK. AFTER PRESSURE BUILD-UP HAS BEEN RELEASED, REMOVE CAP FROM FILLER NECK.

(2) Drain a small amount of coolant from the radiator until the ends of the radiator tubes are visible through the filler neck. Idle the engine at normal operating temperature. If coolant is flowing past the exposed tubes, the coolant is circulating.

(3) Remove the hose clamps and hoses from radia-

tor.

(4) Remove the coolant reserve/overflow tank hose

from the radiator filler neck.

(5) Remove the coolant reserve/overflow tank (5.9L) or the coolant degas container(3.7L/4.7L) from the fan shroud (pull straight up). The tank slips into slots on the fan shroud.

(6) Unclip the power steering hoses from the fan shroud.

(7) Disconnect the electrical connectors at the windshield washer reservoir tank and remove the tank.

(8) Remove the fan shroud mounting bolts and pull up and out of the radiator tank clips (Fig. 33). Position shroud rearward over the fan blades towards engine.

(9) Disconnect the transmission cooler lines from the transmission cooler, then plug the transmission lines and cooler to prevent leakage.

(10) Disconnect the power steering lines from the power steering cooler, then plug the power steering lines and cooler to prevent leakage.

(11) Remove the two radiator upper mounting bolts (Fig. 34).

(12) Lift the radiator straight up and out of the engine compartment. Take care not to damage cooling fins or tubes on the radiator and oil coolers when removing.

REMOVAL

(1) Disconnect battery negative cables.

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7 - 58 ENGINE DR

RADIATOR (Continued)

NOTE: The radiator is equipped with one alignment dowel on the bottom of the outlet tank and one retaining bracket on the front side of the inlet tank. Both features have rubber insulators attached to them that must be present. The alignment dowel fits into a hole at the bottom of the front end sheet metal vertical support post and the support bracket rests on top of the lower radiator closure tube.

CLEANING

Clean radiator fins are necessary for good heat transfer. The radiator and oil cooler fins should be cleaned when an accumulation of debris has occurred. With the engine cold, apply cold water and compressed air to the back (engine side) of the radiator to flush the radiator and/or oil coolers of debris.

INSPECTION

Inspect the radiator side tanks for cracks, broken or missing fittings also inspect the joint where the tanks seam up to the radiator core for signs of leak-

Fig. 33 Fan Shroud

1 - RADIATOR 2 - SCREWS 3 - FAN SHROUD 4 - SLIDE MOUNT

age and/or deteriorating seals.

Inspect radiator core for corroded, bent or missing cooling fins. Inspect the core for bent or damaged cooling tubes.

INSTALLATION

(1) Position the fan shroud over the fan blades rearward towards engine.

(2) Install the rubber insulators to the lower radiator mounting features (alignment dowel and support bracket at the lower part of the radiator).

(3) Lower the radiator into position while guiding the alignment dowel into the vertical post bracket. Position and seat the lower radiator support bracket onto the lower radiator closure tube.

(4) Install the upper radiator mounting bolts. Tighten bolts to 8.5 N·m (75 in. lbs.).

(5) Connect the lower radiator hose and install the clamp in the proper position.

(6) Connect the power steering hoses to the power steering oil cooler and install the clamps.

(7) Connect the transmission oil cooler lines to the transmission oil cooler and install the secondary latches.

(8) Position the fan shroud into the mounting clips on the radiator tanks and secure with bolts. Tighten the bolts to 8.5 N·m (75 in. lbs.).

Fig. 34 Radiator

1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT

(9) Secure the power steering hoses into the clip on the lower fan shroud.

(10) Install the windshield washer reservoir tank and connect the hose and electrical connector.

(11) Install coolant reserve/overflow container hose(s) to radiator filler neck and secure properly with clamps.

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DR ENGINE 7 - 59

RADIATOR (Continued)

(12) Install coolant reserve/overflow container or degas container to fan shroud and tighten the bolts to 8.5 N·m (75 in. lbs.).

(13) Connect upper radiator hose and install clamp.

(14) Install battery negative cable.

(15) Fill cooling system with coolant (Refer to 7 COOLING - STANDARD PROCEDURE).

(16) Operate the engine until it reaches normal operating temperature. Check cooling system fluid levels.

RADIATOR - 5.9L DIESEL

DESCRIPTION

The radiator is a aluminum cross-flow design with horizontal tubes through the radiator core and vertical plastic side tanks (Fig. 35).

This radiator does not contain an internal transmission oil cooler

DIAGNOSIS AND TESTING—RADIATOR COOLANT FLOW

Use the following procedure to determine if coolant

is flowing through the cooling system.

(1) Idle engine until operating temperature is reached. If the upper radiator hose is warm to the touch, the thermostat is opening and coolant is flowing to the radiator.

REMOVAL

(1) Disconnect both battery negative cables.

Fig. 35 Radiator — Typical

1 - SCREW 2 - SCREW 3 - LOWER MOUNT 4 - RADIATOR 5 - DRAINCOCK 6 -LOWER MOUNT

OPERATION

The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radiator core to cool the engine.

WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAINCOCK WITH THE SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

(2) Drain the cooling system (Refer to 7 - COOL-

ING - STANDARD PROCEDURE).

WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER

6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20) MAY BE USED FOR LARGER CLAMPS. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with a matching number or letter.

(3) Remove air box and turbocharger inlet tube.

(4) Remove coolant tank hose, washer bottle hose and the positive battery cable from the fastening clips located on top of the radiator.

(5) Remove hose clamps and hoses from radiator.

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7 - 60 ENGINE DR

RADIATOR - 5.9L DIESEL (Continued)

(6) Remove the power steering cooler mounting bolts and position the power steering cooler out of the way.

(7) Disconnect the transmission cooler lines at the transmission. The transmission cooler will remain on the radiator and can be removed as an assembly.

(8) Remove the lower shroud assembly and the electronic viscous fan wiring from the upper shroud assembly.

(9) Remove the two radiator upper mounting bolts (Fig. 36).

Fig. 36 Fan Shroud Mounting—5.9L Diesel Engine

1 - RADIATOR SUPPORT 2 - UPPER FAN SHROUD 3 - BOLTS (2) 4 - LOWER FAN SHROUD 5 - RADIATOR

(10) Lift radiator straight up and out of engine compartment. The bottom of the radiator is equipped with two alignment dowels that fit into holes in the lower radiator support panel. Rubber biscuits (insulators) are installed to these dowels. Take care not to damage cooling fins or tubes on the radiator and air conditioning condenser when removing.

CLEANING

INSPECTION

Inspect the radiator side tanks for cracks, broken or missing fittings also inspect the joint where the tanks seam up to the radiator core for signs of leakage and/or deteriorating seals.

Inspect radiator core for corroded, bent or missing cooling fins. Inspect the core for bent or damaged cooling tubes.

INSTALLATION

(1) Install rubber insulators to alignment dowels at lower part of radiator.

(2) Lower the radiator into position while guiding the two alignment dowels into lower radiator support. Different alignment holes are provided in the lower radiator support for each engine application.

(3) Install two upper radiator mounting bolts. Tighten bolts to 11 N·m (95 in. lbs.) torque.

(4) Connect both radiator hoses and install hose clamps.

(5) Connect transmission cooler lines to radiator tank. Inspect quick connect fittings for debris and install until an audible “click” is heard. Pull apart to verify connection.

(6) Position power steering cooler on the radiator and tighten nuts to 8.5M·N (75 in. lbs.)

(7) Attach electronic viscous fan wiring to upper shroud ands install lower shroud.

(8) Position coolant recover tank hose, washer bottle hose and the positive battery cable into the clips located on the top of the radiator.

(9) Install air box and turbocharger inlet hose. Tighten clamps to 4 N·M (35 in. lbs.).

(10) Position heater controls to full heat position.

(11) Fill cooling system with coolant (Refer to 7 COOLING - STANDARD PROCEDURE).

(12) Operate engine until it reaches normal temperature. Check cooling system and automatic transmission (if equipped) fluid levels.

RADIATOR PRESSURE CAP

DESCRIPTION

All cooling systems are equipped with a pressure cap (Fig. 37). For 5.9L engines, the pressure cap is located on top of the radiator outlet tank. For the

3.7L/4.7L engines, the pressure cap is located on top of the coolant degas container. The cap releases pressure at some point within a range of 97-to-124 kPa (14-to-18 psi). The pressure relief point (in pounds) is engraved on top of the cap

The cooling system will operate at pressures slightly above atmospheric pressure. This results in a higher coolant boiling point allowing increased radiator cooling capacity. The cap contains a spring-

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DR ENGINE 7 - 61

RADIATOR PRESSURE CAP (Continued)

loaded pressure relief valve. This valve opens when system pressure reaches the release range of 97-to124 kPa (14-to-18 psi).

A rubber gasket seals the radiator filler neck. This is done to maintain vacuum during coolant cool-down and to prevent leakage when system is under pressure.

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING—RADIATOR CAP-TO-FILLER NECK SEAL

The pressure cap upper gasket (seal) pressure relief can be tested by removing overflow hose from the radiator filler neck tube. Attach the hose of the pressure tester tool 7700 (or equivalent) to the tube. It will be necessary to disconnect hose from its adapter for the filler neck. Pump air into radiator. The pressure cap upper gasket should relieve at 69 to 124kPa (10 to 18 psi) and hold pressure at a minimum of 55 kPa (8 psi).

WARNING: THE WARNING WORDS —DO NOT OPEN HOT— ON RADIATOR PRESSURE CAP, ARE A SAFETY PRECAUTION. WHEN HOT, PRESSURE BUILDS UP IN COOLING SYSTEM. TO PREVENT SCALDING OR INJURY, RADIATOR CAP SHOULD NOT BE REMOVED WHILE SYSTEM IS HOT AND/OR UNDER PRESSURE.

Do not remove the radiator cap at any time except for the following purposes:

(1) Check and adjust antifreeze freeze point.

(2) Refill the system with new antifreeze.

(3) Conducting service procedures.

(4) Checking for vacuum leaks.

Fig. 37 Radiator Pressure Cap - Typical

1 - FILLER NECK SEAL 2 - VACUUM VENT VALVE 3 - PRESSURE RATING 4 - PRESSURE VALVE

OPERATION

A vent valve in the center of the cap will remain shut as long as the cooling system is pressurized. As the coolant cools, it contracts and creates a vacuum in the cooling system. This causes the vacuum valve to open and coolant in the reserve/overflow container to be drawn through the recovery hose connecting the filler neck and reserve/overflow container. If the vacuum valve is stuck shut, or the recovery hose is kinked, radiator hoses will collapse on cool down.

For the 3.7L/4.7L engine, the vacuum valve will open and relieve the vacuum pressure in the cooling system.

WARNING: IF VEHICLE HAS BEEN RUN RECENTLY, WAIT AT LEAST 15 MINUTES BEFORE REMOVING RADIATOR CAP. WITH A RAG, SQUEEZE RADIATOR UPPER HOSE TO CHECK IF SYSTEM IS UNDER PRESSURE. PLACE A RAG OVER CAP AND WITHOUT PUSHING CAP DOWN, ROTATE IT COUNTERCLOCKWISE TO FIRST STOP. ALLOW FLUID TO ESCAPE THROUGH THE COOLANT RESERVE/ OVERFLOW HOSE INTO RESERVE/OVERFLOW TANK. SQUEEZE RADIATOR UPPER HOSE TO DETERMINE WHEN PRESSURE HAS BEEN RELEASED. WHEN COOLANT AND STEAM STOP BEING PUSHED INTO TANK AND SYSTEM PRESSURE DROPS, REMOVE RADIATOR CAP COMPLETELY.

DIAGNOSIS AND TESTING - RADIATOR CAP

Remove the cap from the radiator. Be sure that the sealing surfaces are clean. Moisten the rubber gasket with water and install the cap on the pressure tester 7700 or an equivalent (Fig. 38).

Operate the tester pump to bring the pressure to 104 kPa (15 psi) on the gauge. If the pressure cap fails to hold pressure of at least 97 kPa (14 psi) replace the cap. Refer to the following CAUTION.

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7 - 62 ENGINE DR

RADIATOR PRESSURE CAP (Continued)

Fig. 39 Radiator Pressure Cap

1 - STAINLESS-STEEL SWIVEL TOP 2 - RUBBER SEALS 3 - VENT VALVE 4 - RADIATOR TANK 5 - FILLER NECK 6 - OVERFLOW NIPPLE 7 - MAIN SPRING 8 - GASKET RETAINER

Fig. 38 Pressure Testing Radiator Cap - Typical

1 - PRESSURE CAP 2 - TYPICAL COOLING SYSTEM PRESSURE TESTER

The pressure cap may test properly while positioned on tool 7700 (or equivalent). It may not hold pressure or vacuum when installed on the radiator. If so, inspect the radiator filler neck and radiator cap’s top gasket for damage. Also inspect for dirt or distortion that may prevent the cap from sealing properly.

CAUTION: Radiator pressure testing tools are very sensitive to small air leaks which will not cause cooling system problems. A pressure cap that does not have a history of coolant loss should not be replaced just because it leaks slowly when tested with this tool. Add water to tool. Turn tool upside down and recheck pressure cap to confirm that cap needs replacement.

CLEANING

Use only a mild soap and water to clean the radiator cap. Using any type of solvent may cause damage to the seal in the radiator cap.

INSPECTION

Hold cap at eye level, right side up. The vent valve (Fig. 39) at bottom of cap should closed. A slight downward pull on the vent valve should open it. If the rubber gasket has swollen and prevents vent valve from opening, replace cap.

Hold cap at eye level, upside down. If any light can be seen between vent valve and rubber gasket, replace cap. A replacement cap must be the type

designed for a coolant reserve/overflow system with a completely sealed diaphragm spring and a rubber gasket. This gasket is used to seal to radiator filler neck top surface. Use of proper cap will allow coolant return to radiator.

WATER PUMP - 5.9L

DESCRIPTION

The water pump is located on the engine front

cover, and has an integral pulley attached (Fig. 40).

The water pump impeller is pressed onto the rear of a shaft that rotates in a bearing pressed into the water pump body. The body has a small hole for ventilation. The water pump seals are lubricated by antifreeze in the coolant mixture. Additional lubrication is not necessary.

OPERATION

A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core, this coolant absorbs the heat generated when the engine is running. The pump is driven by the engine crankshaft via a drive belt.

DIAGNOSIS AND TESTING—WATER PUMP

A quick test to determine if pump is working is to check if heater warms properly. A defective water pump will not be able to circulate heated coolant through the long heater hose to the heater core.

Page 63

DR ENGINE 7 - 63

WATER PUMP - 5.9L (Continued)

Fig. 40 Water Pump Location — Typical

1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY

REMOVAL

The water pump on all models can be removed without discharging the air conditioning system (if equipped).

The water pump on all gas powered engines is bolted directly to the engine timing chain case/cover.

On the 5.9L gas powered engine, a gasket is used as a seal between the water pump and timing chain case/cover.

If water pump is replaced because of bearing/shaft damage or leaking shaft seal, the mechanical cooling fan assembly should also be inspected. Inspect for fatigue cracks, loose blades or loose rivets that could have resulted from excessive vibration. Replace fan if any of these conditions are found. Also check condition of the thermal viscous fan drive (Refer to 7 COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - DIAGNOSIS AND TESTING).

(1) Disconnect the negative cable.

(2) Drain cooling system (Refer to 7 - COOLING STANDARD PROCEDURE).

Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

(3) Remove the radiator fan (Refer to 7 - COOLING/ENGINE/RADIATOR FAN - REMOVAL)

(4) Remove accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL) (Fig. 41).

(5) Remove the lower radiator hose and heater hose from the water pump.

(6) Loosen the heater hose coolant return tube mounting bolt (Fig. 42) and remove the tube from the water pump. Discard the old tube O-ring.

(7) Remove the water pump mounting bolts (Fig.

43).

Fig. 41 Belt Tensioner 5.9L V-8 Engine

1 - IDLER PULLEY 2 - TENSIONER 3 - FAN BLADE

Fig. 42 Coolant Return Tube 5.9L

1 - COOLANT RETURN TUBE 2 - WATER PUMP 3 - TUBE MOUNTING BOLT 4 - O-RING

(8) Loosen the clamp at the water pump end of

bypass hose (Fig. 42). Slip the bypass hose from the

Page 64

7 - 64 ENGINE DR

WATER PUMP - 5.9L (Continued)

(6) Install the coolant return tube and its mounting bolt to the engine (Fig. 42). Be sure the slot in the tube bracket is bottomed to mounting bolt. This will properly position return tube.

(7) Connect the radiator lower hose to the water pump.

(8) Connect the heater hose and hose clamp to the coolant return tube.

(9) Install drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION) (Fig. 41).

(10) Install the fan (Refer to 7 - COOLING/ENGINE/RADIATOR FAN - INSTALLATION)

(11) Fill cooling system (Refer to 7 - COOLING STANDARD PROCEDURE).

(12) Connect negative battery cable.

Fig. 43 Water Pump Bolts - 5.9L V-8 Gas Engine -

Typical

1 - WATER PUMP MOUNTING BOLTS

(13) Start and warm the engine. Check for leaks.

WATER PUMP - 3.7L/4.7L

water pump while removing pump from vehicle. Do not remove the clamp from the bypass hose.

(9) Discard the old gasket.

DESCRIPTION

CAUTION: Do not pry the water pump at timing chain case/cover. The machined surfaces may be damaged resulting in leaks.

CLEANING

Clean gasket mating surfaces as necessary.

INSPECTION

Visually inspect the water pump and replace if it

has any of the following conditions:

• The body is cracked or damaged

• Water leaks from the shaft seal. This is evident

by traces of coolant below the vent hole

• Loose or rough turning bearing.

• Impeller rubbing the pump body

INSTALLATION

(1) Clean the gasket mating surfaces.

(2) Using a new gasket, install the water pump to the engine as follows: Guide the water pump tube into the bypass hose as the pump is being installed. Install the water pump bolts (Fig. 43). Tighten the water pump mounting bolts to 40 N·m (30 ft. lbs.) torque.

(3) Position the bypass hose clamp to the bypass hose.

(4) Spin the water pump to be sure that the pump impeller does not rub against the timing chain case/ cover.

(5) Install a new o-ring to the heater hose coolant return tube (Fig. 42). Coat the new o-ring with antifreeze before installation.

DESCRIPTION—WATER PUMP

A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core. The pump is driven from the engine crankshaft by a single serpentine drive belt.

The water pump impeller is pressed onto the rear of a shaft that rotates in bearings pressed into the housing. The housing has two small holes to allow seepage to escape. The water pump seals are lubricated by the antifreeze in the coolant mixture. No additional lubrication is necessary.

Both heater hoses are connected to fittings on the timing chain front cover. The water pump is also mounted directly to the timing chain cover and is equipped with a non serviceable integral pulley (Fig.

44).

DESCRIPTION—WATER PUMP BYPASS

The 3.7L and 4.7L engine uses an internal water/ coolant bypass system. The design uses galleries in the timing chain cover to circulate coolant during engine warm-up preventing the coolant from flowing through the radiator. The thermostat uses a stub shaft located at the rear of the thermostat (Fig. 45) to control flow through the bypass gallery.

OPERATION

OPERATION—WATER PUMP

A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold,

Page 65

DR ENGINE 7 - 65

WATER PUMP - 3.7L/4.7L (Continued)

Fig. 44 Water Pump and Timing Chain Cover

1 - INTEGRAL WATER PUMP PULLEY 2 - TIMING CHAIN COVER 3 - THERMOSTAT HOUSING 4 - HEATER HOSE FITTINGS 5 - WATER PUMP

radiator core, cooling system hoses and heater core, this coolant absorbs the heat generated when the engine is running. The pump is driven by the engine crankshaft via a drive belt.

OPERATION—WATER PUMP BYPASS

When the thermostat is in the closed position the bypass gallery is not obstructed allowing 100% flow. When the thermostat is in the open position the stub shaft enters the bypass gallery obstructing bypass coolant flow by 50%. This design allows the coolant to reach operating temperature quickly when cold, while adding extra cooling during normal temperature operation.

REMOVAL

The water pump on 3.7L/4.7L engines is bolted directly to the engine timing chain case cover.

(1) Disconnect the negative battery cable.

(2) Drain cooling system (Refer to 7 - COOLING STANDARD PROCEDURE).

(3) Remove fan/viscous fan drive assembly from water pump (Fig. 46) (Refer to 7 - COOLING/ENGINE/FAN DRIVE VISCOUS CLUTCH - REMOVAL). Do not attempt to remove fan/viscous fan drive assembly from vehicle at this time.

WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES.

Fig. 45 Water/Coolant Bypass Flow and Thermostat

1 - FROM HEATERAND DEGAS CONTAINER 2 - FROM RADIATOR 3 - TO WATER PUMP 4 - ENGINE BYPASS 5 - THERMOSTAT

WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter and width.

(4) If the water pump is being replaced, do not unbolt the fan blade assembly from the thermal viscous fan drive.

(5) Remove the radiator fan (Refer to 7 - COOLING/ENGINE/RADIATOR FAN - REMOVAL).

(6) Remove accessory drive belt (Fig. 47) (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(7) Remove the lower radiator hose clamp and remove the lower hose at the water pump.

(8) Remove the water pump mounting bolts.

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7 - 66 ENGINE DR

WATER PUMP - 3.7L/4.7L (Continued)

(9) Remove the water pump and gasket. Discard gasket.

CLEANING

Clean the gasket mating surface. Use caution not to damage the gasket sealing surface.

INSPECTION

Inspect the water pump assembly for cracks in the housing, water leaks from shaft seal, worn bearing or impeller rubbing either the pump body or timing chain case/cover.

INSTALLATION

The water pump on 3.7L/4.7L engine is bolted directly to the engine timing chain case cover.

(1) Clean the gasket mating surfaces.

(2) Using a new gasket, position water pump and install the mounting bolts. (Fig. 48). Tighten the water pump mounting bolts to 58 N·m (43 ft. lbs.).

Fig. 46 Viscous Fan and Fan Drive 4.7L Engine

1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER PINS 8346 2-FAN

Fig. 48 Water Pump Installation—3.7L/4.7L Typical

1 - WATER PUMP 2 - TIMING CHAIN COVER

Fig. 47 Automatic Belt Tensioner—4.7L

1 - AUTOMATIC TENSIONER 2 - WATER PUMP PULLEY

CAUTION: Do not pry water pump at timing chain case/cover. The machined surfaces may be damaged resulting in leaks.

(3) Spin the water pump to be sure that the pump impeller does not rub against the timing chain case/ cover.

(4) Connect the radiator lower hose to the water pump.

(5) Relax the tension from the belt tensioner (Fig.

47). Install the drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

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DR ENGINE 7 - 67

WATER PUMP - 3.7L/4.7L (Continued)

CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to (Fig. 49) for the correct belt routing. Or, refer to the Belt Routing Label located in the engine compartment. The correct belt with correct length must be used.

antifreeze in the coolant mixture. Additional lubrication is not necessary.

OPERATION

The diesel engine water pump draws coolant from radiator outlet and circulates it through engine, heater core and back to radiator inlet. The crankshaft pulley drives the water pump with a serpentine drive belt.

DIAGNOSIS AND TESTING—WATER PUMP

A quick test to determine if pump is working is to check if heater warms properly. A defective water pump will not be able to circulate heated coolant through the long heater hose to the heater core.

REMOVAL

(1) Disconnect battery negative cables.

(2) Drain cooling system (Refer to 7 - COOLING STANDARD PROCEDURE).

(3) Remove the accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(4) Remove water pump mounting bolts (Fig. 50).

Fig. 49 Belt Routing 3.7L

1 - GENERATOR PULLEY 2 - ACCESSORY DRIVE BELT 3 - POWER STEERING PUMP PULLEY 4 - CRANKSHAFT PULLEY 5 - IDLER PULLEY 6 - TENSIONER 7 - A/C COMPRESSOR PULLEY 8 - WATER PUMP PULLEY

(6) Install the radiator fan (Refer to 7 - COOLING/

ENGINE/RADIATOR FAN - INSTALLATION).

(7) Fill cooling system (Refer to 7 - COOLING -

STANDARD PROCEDURE).

(8) Connect the negative battery cable. (9) Start and warm the engine. Check for leaks.

WATER PUMP - 5.9L DIESEL

DESCRIPTION

The water pump is mounted to the front of the engine block between the automatic belt tensioner and the fan drive pulley.

Fig. 50 Water Pump Removal/Installation

1 - O-RING SEAL (SQUARE) 2 - WATER PUMP 3 - BOLT (2)

(5) Clean water pump sealing surface on cylinder

block.

CLEANING

Clean gasket mating surfaces as necessary.

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7 - 68 ENGINE DR

WATER PUMP - 5.9L DIESEL (Continued)

INSPECTION

Visually inspect the water pump and replace if it has any of the following conditions:

• The body is cracked or damaged

• Water leaks from the shaft seal. This is evident

by traces of coolant below the vent hole

• Loose or rough turning bearing.

• Impeller rubbing the pump body

INSTALLATION

(1) Install new O-ring seal in groove on water pump (Fig. 51).

generator or A/C compressor from their mounting bracket is not necessary. Also, discharging the A/C system is not necessary. Do not remove any refrigerant lines from A/C compressor.

Fig. 51 Pump O-ring Seal

1 - O-RING SEAL 2 - GROOVE 3 - WATER PUMP

(2) Install water pump. Tighten mounting bolts to 24 N·m (18 ft. lbs.) torque.

(3) Install accessory drive belt. Refer to procedure in this group.

(4) Install the bolt retaining the wiring harness near top of water pump.

(5) Fill cooling system. Refer to Refilling Cooling System in this section.

(6) Connect both battery cables.

(7) Start and warm the engine. Check for leaks.

WATER PUMP INLET TUBE -

5.9L

REMOVAL

REMOVAL - WATER PUMP BYPASS HOSE WITH AIR CONDITIONING

If equipped with A/C, the generator and A/C compressor along with their common mounting bracket (Fig. 52) must be partially removed. Removing the

Fig. 52 Generator - A/C Compressor Mounting

Bracket - Typical

WARNING: THE A/C SYSTEM IS UNDER PRESSURE EVEN WITH THE ENGINE OFF. REFER TO REFRIGERANT WARNINGS IN SECTION 24 - HEATING AND AIR CONDITIONING.

(1) Disconnect the negative battery cable.

(2) Partially drain the cooling system (Refer to 7 COOLING - STANDARD PROCEDURE).Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

(3) Remove the upper radiator hose clamp at the radiator. A special clamp tool must be used to remove the constant tension clamps. Removethe hose at the radiator.

(4) Unplug the wiring harness from the A/C compressor.

(5) Remove the air cleaner assembly.

(6) Remove the accessory drive belt (Refer to 7 COOLING/ACCESSORY DRIVE/DRIVE BELTS REMOVAL).

(7) The drive belt idler pulley must be removed to gain access to one of the A/C compressor/generator bracket mounting bolts. Remove the idler pulley bolt and remove idler pulley (Fig. 53).

(8) Remove the engine oil dipstick tube mounting bolt at the side of the A/C-generator mounting bracket.

(9) Disconnect the throttle body control cables.

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DR ENGINE 7 - 69

WATER PUMP INLET TUBE - 5.9L (Continued)

(12) Remove the remaining bracket-to-engine bolts (Fig. 55).

Fig. 53 Idler Pulley - 5.9L V-8 Gas Engine

(10) Remove the heater hose coolant return tube mounting bolt (Fig. 54) (Fig. 55) and remove the tube from the engine. Discard the old tube O-ring.

Fig. 55 Bracket Bolts - 5.9L V-8 Gas

1 - COOLANT TUBE MOUNTING BOLT 2 - BRACKET MOUNTING BOLTS

(13) Lift and position the generator and A/C compressor (along with their common mounting bracket) to gain access to the bypass hose. A block of wood may be used to hold the assembly in position.

(14) Loosen and position both hose clamps to the center of the bypass hose. A special clamp tool must be used to remove the constant tension clamps. Remove the hose from the vehicle.

REMOVAL - WATER PUMP BYPASS HOSE WITHOUT AIR CONDITIONING

A water pump bypass hose (Fig. 56) is used between the intake manifold and water pump on all gas powered engines. To test for leaks, (Refer to 7 COOLING - DIAGNOSIS AND TESTING).

(1) Partially drain the cooling system (Refer to 7 COOLING - STANDARD PROCEDURE). Do not waste reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

Fig. 54 Coolant Return

1 - COOLANT RETURN TUBE 2 - WATER PUMP 3 - TUBE MOUNTING BOLT 4 - O-RING

(11) Remove the bracket-to-intake manifold bolts

(number 1 and 2 (Fig. 52).

Page 70

7 - 70 ENGINE DR

WATER PUMP INLET TUBE - 5.9L (Continued)

Fig. 56 Water Pump Bypass Hose - Typical

1 - WATER PUMP BYPASS HOSE 2 - FAN BLADE ASSEMBLY 3 - VISCOUS FAN DRIVE 4 - WATER PUMP AND PULLEY

CAUTION: A number or letter is stamped into the tongue of the constant tension clamps. If replacement is necessary, use only an original equipment clamp with a matching number or letter and width.

(2) Loosen both of the bypass hose clamps and

position them to the center of the hose.

(3) Removethe hose from the vehicle.

INSTALLATION

INSTALLATION - WATER PUMP BYPASS HOSE WITH AIR CONDITIONING

(1) Position the bypass hose clamps to the center

of the bypass hose.

(2) Install the bypass hose to the engine. (3) Secure both of the hose clamps. (4) Install the generator-A/C mounting bracket

assembly to the engine. Tighten bolt number 1 (Fig.

53) to 41 N·m (30 ft. lbs.). Tighten bolt number 2 (Fig. 53) to 28 N·m (20 ft. lbs.). Tighten bracket mounting bolts (Fig. 53) (Fig. 53) to 40 N·m (30 ft. lbs.).

(5) Install a new O-ring to the heater hose coolant return tube. Coat the new O-ring with antifreeze before installation.

(6) Install the coolant return tube and its mounting bolt to the engine.

(7) Connect the throttle body control cables.

(8) Install the oil dipstick mounting bolt.

(9) Install the idler pulley. Tighten the bolt to 41 N·m (30 ft. lbs.) (Fig. 57).

(10) Install the drive belt (Refer to 7 - COOLING/ ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

Fig. 57 Tensioner Mounting

1 - DOWEL PIN HOLE 2 - TENSIONER MOUNTING BRACKET

CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION). The correct belt with the correct length must be used.

(11) Install the air cleaner assembly. (12) Install the upper radiator hose to the radiator. (13) Connect the throttle cable to the clip at the

radiator fan shroud.

(14) Connect the wiring harness to the A/C com-

pressor.

(15) Fill the cooling system (Refer to 7 - COOLING

- STANDARD PROCEDURE). (16) Start and warm the engine. Check for leaks.

INSTALLATION - WATER PUMP BYPASS HOSE WITHOUT AIR CONDITIONING

(1) Position the bypass hose clamps to the center

of the bypass hose.

(2) Install the bypass hose tothe engine. (3) Secure both of the hose clamps. (4) Fill the cooling system (Refer to 7 - COOLING

- STANDARD PROCEDURE). (5) Start and warm the engine. Check for leaks.

WATER PUMP - 5.7L

REMOVAL

(1) Disconnect negative battery cable. (2) Drain coolant. (3) Remove serpentine belt. (4) Remove fan clutch assembly. (5) Remove coolant fill bottle.

Page 71

DR ENGINE 7 - 71

WATER PUMP - 5.7L (Continued)

(6) Disconnect washer bottle wiring and hose. (7) Remove fan shroud assembly. (8) Remove A/C compressor and genterator brace. (9) Remove idler pulleys. (10) Remove belt tensioner assembly. (11) Remove upper and lower radiator hoses. (12) Remove heater hoses. (13) Remove water pump mounting bolts and

remove pump.

INSTALLATION

(1) Install water pump and mounting bolts.

Tighten moubting bolts to 24 N·m (18 ft. lbs.).

(2) Install heater hoses. (3) Install upper and lower radiator hoses. (4) Install belt tensioner assembly. (5) Install idler pulleys. (6) Install A/C compressor and alternator brace.

Tighten bolt and nuts to 28 N·m (21 ft. lbs.).

(7) Install fan shroud assembly. (8) Connect washer bottle wiring and hose. (9) Install coolant fill bottle. (10) Install fan clutch assembly. (11) Install serpentine belt. (12) Connect negative battery cable. (13) Fill coolant. (14) Pressure test coolant system

Page 72

7 - 72 TRANSMISSION DR

TRANSMISSION

TABLE OF CONTENTS

page page

TRANS COOLER

DESCRIPTION

DESCRIPTION ........................72

OPERATION ...........................72

REMOVAL .............................72

DISASSEMBLY - 5.9L ONLY ...............73

ASSEMBLY - 5.9L ONLY ..................73

INSTALLATION .........................73

TRANS COOLER

DESCRIPTION

An air-to-oil transmission oil cooler is standard on all engine packages. The transmission oil cooler is mounted to the front of the radiator above the power steering cooler (Fig. 1).

DESCRIPTION

An air-to-oil transmission oil cooler is standard on all engine packages. The transmission oil cooler is mounted to the front of the radiator above the power steering cooler (Fig. 2).

TRANS COOLER - 5.9L DIESEL

DESCRIPTION .........................73

OPERATION ...........................74

REMOVAL

REMOVAL—AIR TO OIL COOLER .........74

REMOVAL—WATER TO OIL COOLER ......74

INSTALLATION

INSTALLATION—AIR TO OIL COOLER .....75

INSTALLATION .......................75

OPERATION

Transmission oil is routed through the cooler where heat is removed from the transmission oil before returning to the transmission. Vehicles equipped with the 5.9L engine have an internal thermostat that controls fluid flow through the cooler.When the transmission fluid is cold ( less than operating temperature) the fluid is routed through the cooler bypass. when the transmission fluid reaches operating temperatures and above, the thermostat closes off the bypass allowing fluid flow through the cooler. The thermostat is serviceable.

NOTE: Vehicles with the 3.7L/4.7L engines are not equipped with the oil cooler thermostat.

REMOVAL

(1) Disconnect the battery negative cable.

(2) Place a drain pan under the oil cooler lines.

Fig. 1 Cooling Module — 5.9L Gas

1 - TRANS OIL COOLER BYPASS (5.9L only) 2 - OIL COOLER THERMOSTATIC BYPASS VALVE (5.9L only) 3 -TRANS OIL COOLER 4 - OIL COOLER MOUNTING BOLT (4) 5 - POWER STEERING COOLER 6 - POWER STEERING COOLER MOUNTING BOLT(2) 7 - TRANS OIL COOLER OUTLET 8 - TRANS OIL COOLER INLET 9 - COOLER LINE CLIP 10 - COOLER LINE CLIP 11 - RADIATOR

(3) Disconnect the transmission oil cooler line quick-connect fitting at the cooler outlet using the quick connect release tool 6935. Plug the cooler lines to prevent oil leakage.

(4) Unsnap the transmission cooler tubes from the radiator tank clips.

Page 73

DR TRANSMISSION 7 - 73

TRANS COOLER (Continued)

Fig. 3 Transmission Oil Cooler Thermostat

Removal/Installation

1 - THERMOSTAT HOUSING 2 - SPRING 3 - END PLUG 4 - SNAP RING 5 - THERMOSTAT

Fig. 2 Cooling Module - 3.7L/4.7L/5.7L

1 - TRANS OIL COOLER 2 - TRANS OIL COOLER MOUNTING BOLT (3) 3 - POWER STEERING OIL COOLER 4 - POWER STEERING OIL COOLER MOUNTING BOLT 5 - TRANS OIL COOLER OUTLET 6 - TRANS OIL COOLER INLET 7 - COOLER LINE CLIP 8 - COOLER LINE CLIP 9 - RADIATOR

(5) Remove the bolts attaching the transmission

cooler to the radiator.

(6) Remove oil cooler from the vehicle. Take care not to damage the radiator core or transmission cooler tubes.

DISASSEMBLY - 5.9L ONLY

NOTE: The transmission oil cooler uses an internal thermostat to control transmission oil flow through the cooler. This thermostat is servicable.

(1) Remove the transmission oil cooler (Refer to 7 COOLING/TRANSMISSION/TRANS COOLER REMOVAL).

(2) Remove the snap ring retaining the thermostat end plug (Fig. 3).

(3) Remove the end plug, thermostat and spring from transmission oil cooler (Fig. 3).

ASSEMBLY - 5.9L ONLY

(1) Throughly clean the thermostat bore on the transmission oil cooler.

(2) Install the new spring, thermostat, end plug and snap ring.

(3) Install the transmission oil cooler (Refer to 7 COOLING/TRANSMISSION/TRANS COOLER INSTALLATION).

INSTALLATION

(1) Position the transmission cooler tubes to the front of the radiator.

(2) Snap the transmission cooler tubes into the clips on the side of the radiator tank.

(3) Install the transmission cooler attaching bolts. Tighten the bolts to 16 N·m (140 in. lbs.).

(4) inspect the quick connect fittings for debris and install the quick connect fitting on the cooler tube until an audible “click” is heard. Pull apart the connection to verify proper installation and install the secondary latches.

(5) Connect the battery negative cable.

(6) Start the engine and check all fittings for leaks.

(7) Check the fluid level in the automatic transmission. Refer to the appropriate transmission section(Refer to 21 - TRANSMISSION/TRANSAXLE/ AUTOMATIC - 45RFE/545RFE/FLUID - STANDARD PROCEDURE) or(Refer to 21 - TRANSMISSION/ TRANSAXLE/AUTOMATIC - 46RE/FLUID - STANDARD PROCEDURE).

TRANS COOLER - 5.9L DIESEL

DESCRIPTION

All diesel models equipped with an automatic transmission are equipped with both a main waterto-oil cooler and a separate air-to-oil cooler. Both cool-

Page 74

7 - 74 TRANSMISSION DR

TRANS COOLER - 5.9L DIESEL (Continued)

ers are supplied as standard equipment on diesel engine powered models when equipped with an automatic transmission.

The main water-to-oil transmission oil cooler is mounted to a bracket on the intake side of the engine (Fig. 4).

The air-to-oil cooler is located in front of and to the left side of the radiator (Fig. 5).

Fig. 4 Transmission Water-To-Oil Cooler—Diesel

Engine—Typical

1 - TRANSMISSION WATER-TO-OIL COOLER

OPERATION

The transmission oil is routed through the main cooler first, then the auxiliary cooler where additional heat is removed from the transmission oil before returning to the transmission. The cooler has an internal thermostat that controls fluid flow through the cooler. When the transmission fluid is cold (less then operating temperature), the fluid is routed through the cooler bypass. When the transmission fluid reaches operating temperatures and above, the thermostat closes off the bypass allowing fluid flow through the cooler. The thermostat is servicable.

Fig. 5 Auxiliary Transmission Oil Cooler—Diesel

Engine

1 - MOUNTING BOLTS 2 - RADIATOR 3 - QUICK-CONNECT FITTINGS 4 - TRANSMISSION OIL COOLER

(2) Place a drain pan under the oil cooler. (3) Raise the vehicle. (4) Disconnect the oil cooler quick-connect fittings

from the transmission lines.

(5) Remove the charge air cooler-to-oil cooler bolt

(Fig. 6).

(6) Remove two mounting nuts.

(7) Remove the oil cooler and line assembly towards the front of vehicle. Cooler must be rotated and tilted into position while removing.

REMOVAL—WATER TO OIL COOLER

CAUTION: If a leak should occur in the water-to-oil cooler mounted to the side of the engine block, engine coolant may become mixed with transmission fluid. Transmission fluid may also enter engine cooling system. Both cooling system and transmission should be drained and inspected in case of oil cooler leakage.

REMOVAL

REMOVAL—AIR TO OIL COOLER

(1) Remove Charge Air Cooler (Refer to 11 EXHAUST SYSTEM/TURBOCHARGER SYSTEM/ CHARGE AIR COOLER AND PLUMBING REMOVAL).

(1) Disconnect both battery negative cables. (2) Remove starter (Refer to 8 - ELECTRICAL/

STARTING/STARTER MOTOR - REMOVAL).

(3) Drain cooling system (Refer to 7 - COOLING -

STANDARD PROCEDURE).

(4) Disconnect coolant lines from cooler.

Page 75

DR TRANSMISSION 7 - 75

TRANS COOLER - 5.9L DIESEL (Continued)

Fig. 6 Auxiliary Transmission Oil Cooler—Diesel

Engine

1 - MOUNTING BOLTS 2 - RADIATOR 3 - QUICK-CONNECT FITTINGS 4 - TRANSMISSION OIL COOLER

(5) Disconnect transmission oil lines from cooler. Plug cooler lines to prevent oil leakage.

(6) Remove cooler bracket to transmission bolt.

(7) Remove two cooler bracket to cooler bolts.

(8) Remove cooler assembly from vehicle. (Fig. 7)

INSTALLATION

INSTALLATION—AIR TO OIL COOLER

(1) Carefully position the oil cooler assembly to the vehicle.

(2) Install two nuts and one bolt. Tighten to 11 N·m (95 in. lbs.) torque.

(3) Connect the quick-connect fittings to the transmission cooler lines.

(4) Install Charge Air Cooler (Refer to 11 EXHAUST SYSTEM/TURBOCHARGER SYSTEM/ CHARGE AIR COOLER AND PLUMBING INSTALLATION).

(5) Start the engine and check all fittings for leaks.

Fig. 7 Transmission Water-To- Oil Cooler—Diesel

1 - TRANSMISSION WATER-TO-OIL COOLER

(6) Check the fluid level in the automatic transmission (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 47RE/FLUID - STANDARD PROCEDURE).

INSTALLATION

(1) Position oil cooler on cylinder block.

(2) Install two mounting bolts to cooler at the cylinder block. Torque bolts to 77N·m (57 ft. lbs.)

(3) Install cooler bracket to transmission adapter bolt. Tighten to 24N·M (18 ft. lbs.).

(4) Connect transmission oil lines to cooler.

(5) Connect coolant hoses to cooler.

(6) Install starter motor (Refer to 8 - ELECTRICAL/STARTING/STARTER MOTOR - INSTALLATION).

(7) Connect battery negative cables.

(8) Fill cooling system (Refer to 7 - COOLING STANDARD PROCEDURE).

(9) Check transmission oil level and fill as necessary (Refer to 21 - TRANSMISSION/TRANSAXLE/ AUTOMATIC - 47RE/FLUID - STANDARD PROCEDURE).

Dodge Factory Cooling 2003 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual