DATE
10/97XK8
303-15
SERVICE
Cooling System Bleed Lines –
Correct Routing – Model Year Differences
Issue:
There are differences between the routing of the cooling system bleed lines between 1997 Model
Year vehicles and 1998 Model Year vehicles. Incorrect routing at the coolant reservoir
connections could lead to air remaining trapped in the cooling system, resulting in overheating of
the engine.
Action:
In case of a customer complaint of engine overheating on an XK8, check that bleed lines are
correctly routed as detailed below.
1997 MY HOSE ROUTING
TECHNICAL BULLETIN
MODEL
VIN
1997 MY-ON
XK8 Range
001001-ON
T
R
JSI-3304
ILLUSTRATION 1
1997 Model Year Condition VIN 001001 - 018107
• Reservoir: Part No. MJA 4400AC for 1997 MY only.
• Bleed line R, Illustration 1, from radiator is connected to front fitting on reservoir
(Illustration 1).
• Bleed Line T from thermostat is connected to rear fitting on reservoir.
Date of issue 10/97 Bulletin Number 303-15 Page 1 of 3
1998 MY HOSE ROUTING
T
JSI-3305
ILLUSTRATION 2
1998 Model Year Condition VIN 018108 ONWARDS
• Reservoir: Part No. changed to MJA 4400AD for 1998 MY.
• Bleed Line T from thermostat is connected to front fitting on the reservoir (Illustration 2).
Note: There is no bleed line from the radiator. This has proved to be
unnecessary.
• The rear fitting of the reservoir (not connected) is plugged.
Page 2 of 3 Bulletin Number 303-15 Date of issue 10/97
1997 MY VEHICLE USING 1998 MY COOLANT RESERVOIR
T
R
ILLUSTRATION 3
RESERVOIR INTERCHANGEABILITY :
It is permissible to use the 1998 MY Reservoir Part No. MJA 4400AD on 1997 Model Year XK8
Models provided that the bleed lines are reversed at the reservoir from the original layout
(Illustration 3) as follows:
• Bleed Line R from the radiator is connected to the blanked-off rear fitting on the Reservoir
(Illustration 3). (This is satisfactory, since air will vent from the radiator by routes other
than this bleed line).
• Bleed Line T from the thermostat is connected to the open front fitting on the Reservoir, as
in Illustration 3. THIS VENT CONNECTION IS MANDATORY. Trapped air in the
cooling system cannot vent if the thermostat bleed line is connected to the plugged rear
fitting.
DIAGNOSIS:
In any case of high coolant temperature/coolant loss, check that the bleed line from the
thermostat is always connected to the correct (open) fitting of the reservoir, especially if a 1998
MY Reservoir may have been installed in a 1997 MY vehicle.
JSI-3306
Warranty Information
This Technical Bulletin is issued for information only, to aid to diagnosis.
Date of issue 10/97 Bulletin Number 303-15 Page 3 of 3
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