Jaguar XK User Manual

V8 XJ Series/XK

DATE

06/97

Amended 09/01

303-11

SERVICE

Poor Heater Performance –

Coolant Specification Change –

Repair Procedure

Remove and destroy Bulletin 303-11, dated 6/97.
Replace with this Bulletin which supersedes
Service Action S813. The procedure has been
rewritten to include V8 XJ Series vehicles.

This Technical Bulletin supersedes Service Action S813 and no further claims will be accepted
under S813. All Warranty Claims must now be made under this Technical Bulletin.

Issue:

On some vehicles within the above VIN ranges, the antifreeze solution in the cooling system may
deteriorate, causing reduced circulation through the heater core, resulting in poor heater
performance. The following procedure has been produced to eliminate this problem:

TECHNICAL BULLETIN

MODEL

1997-99 MY XK Range

1998-99 MY V8 XJ Series

VIN

001001-042635
812256-878274

Action:

In case of a customer complaint of lack of heat from the heating system on a vehicle within the
above VIN ranges, a Workshop Procedure has been produced to eliminate the problem.

Workshop Procedure

STEP 1: HEATER CORE COOLANT CIRCULATION TEST

Note: This procedure is required for all vehicles produced prior to the
introduction of XLC Extended Life Coolant (introduced after VIN 042635
XK Range vehicles and VIN 878274 for V8 XJ Series vehicles), and have
experienced low heater performance and where heater blocking is suspected.

1. Start and run the engine at approximately 2000 rpm until normal coolant temperature is
reached.

2. Press heater auto switch to ‘HI’ setting and press the A/C switch, thus selecting maximum
heater output temperature and maximum fan speed.

Date of issue 06/97 Amended 09/01 Bulletin Number 303-11 Page 1 of 9

LEFT SIDE FOOTWELL DUCT

ILLUSTRATION 1

3. Power the left side seat fully rearward and place the probe of an electronic thermometer in
the left side foot well outlet duct, ensuring the probe is in the hot air stream and not in
contact with the duct (Illustration 1). Maintain the engine speed at 2000 rpm and allow the
temperature reading to stabilize.

4. Switch off the engine and return the seat to its normal position.

Note: If a temperature reading of LESS than 40 °C (104 °F) is indicated, the
coolant circulation rate through the heater core is unsatisfactory. In this
event, proceed to Step 2 Chemical flushing procedure.

If a temperature reading of MORE than 40 °C (104 °F) has been indicated, the coolant
circulation rate through the heater core is satisfactory. In this event, the heater system is working
correctly and no further action is required.

STEP 2: CHEMICAL FLUSHING PROCEDURE

1. Release and open hood.

2. Place covers over the fenders.

3. Remove the pressure cap from the coolant header tank.

Warning: The cooling system may be pressurized and hot.

4. Raise the vehicle on lift.

5. On XK series vehicles only, remove the generator-cooling duct.

6. On all vehicles, position a suitable container under the radiator and remove the radiator
drain plug.

Warning: Coolant will be hot!

7. Allow the cooling system to drain as much as possible.

Caution: Immediately wash away any coolant spilled on the vehicle

bodywork.

8. In place of the radiator drain plug, install and tighten the radiator flushing adaptor tool. (XK

Page 2 of 9 Bulletin Number 303-11 Date of issue 06/97 Amended 09/01

Series vehicles Part Number 100-020, V8 XJ Series vehicles Part Number 100-022).

9. Connect a suitable hose to the adaptor using a worm drive clip to retain the hose.

Note: The hose must be long enough to enable coolant subsequently flushed
from the system to be drained without any possibility of the flushing solution
coming into contact with the vehicle bodywork.

Note: Suitably clamp the hose to prevent water flowing during the following
operations:

10. Remove the container from under the vehicle and lower the lift.

11. Place a cloth below the coolant header tank.

12. Remove the clip on the hose from the header tank to recovery bottle and disconnect the
hose.

13. For access on XK series vehicles, release and remove the air cleaner cover, mass air flow
sensor and air intake hose assembly. For access on V8 XJ series vehicles, remove the
engine compartment rear cover.

CLAMP INSTALLED ON BYPASS HOSE

ILLUSTRATION 2

14. On all vehicles, install a suitable clamp on the heater bypass hose between the one-way
valve and the T-piece (Illustration 2).

15. On XK series vehicles, reinstall the air cleaner cover, mass air flow sensor and air intake
assembly.

16. On all vehicles, remove the air purge breather cap and refill the cooling system with clean
plain water via the header tank, until the level stabilizes at the top of the breather neck.

17. Reinstall the air purge breather cap.

18. Fill up coolant header tank.

19. Install and tighten coolant pressure cap.

20. Start and run the engine at approximately 2000 rpm for 5 minutes with the climate controls
set as previously.

21. Switch off the engine.

Date of issue 06/97 Amended 09/01 Bulletin Number 303-11 Page 3 of 9