Dodge Factory Cooling 2003 Service Manual

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).

7 - 2 COOLING DR

COOLING (Continued)

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).

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

7 - 4 COOLING DR

COOLING (Continued)

Fig. 3 Cooling System Circulation—Diesel Engine

DR COOLING 7 - 5

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

7 - 6 COOLING DR

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.

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)

7 - 8 COOLING DR

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.

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.

7 - 10 COOLING DR

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

DR COOLING 7 - 11

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.

7 - 12 COOLING DR

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.

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.

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).

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.

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.

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.

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.

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.

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

DR COOLING 7 - 21

COOLING (Continued)

Cooling System Pressure Tester - 7700A

Adapter Pins 8346

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.

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).

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