Date of issue 06/97 Amended 09/01 Bulletin Number 303-11 Page 1 of 9
V8 XJ Series/XK
1997-99 MY XK Range
1998-99 MY V8 XJ Series
Poor Heater Performance –
Coolant Specification Change –
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.
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:
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.
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
2. Press heater auto switch to ‘HI’ setting and press the A/C switch, thus selecting maximum
heater output temperature and maximum fan speed.