Jaguar XK Misc Document Poor Heater Performance PDF | Page 2

Page 2 of 9 Bulletin Number 303-11 Date of issue 06/97 Amended 09/01
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
ILLUSTRATION 1
LEFT SIDE FOOTWELL DUCT