coolant level JAGUAR S TYPE 1999 1.G Powertrain Manual

V6 Engine AJ-V6/AJ28
36
Fail Safe Cooling System
A unique feature of the V6 engine is the use of a fail safe cooling strategy, controlled by the EMS, in the
event of coolant loss leading to rising engine temperatures. The principle of the strategy involves
switching off one or more fuel injectors to inhibit combustion and reduce heat, thus allowing the flow of
ambient intake air to further cool the selected cylinders. By cycling the selected cylinders, ie switching
different injectors off for a period and in a sequence determined by EMS parameters, overall engine
temperature can be controlled sufficiently to allow the vehicle to be driven, at reduced power, for a
short distance. Throughout the malfunction period, instrument panel messages and warnings advise the
driver of the current status of the cooling system as described below.
Driver Indication and EMS Action
The fail safe strategy moves though different stages depending on engine temperature:
¥ Temperatures below 122û C (250û F) are within the normal range. At high temperatures below this
level the temperature gauge pointer enters the red zone.
¥ If the temperature rises to between 122û C - 127û C (250û F to 260û F) no action is taken by the EMS
which affects engine running but the following indications appear:
Temperature gauge pointer in red zone
Message Centre HIGH ENGINE TEMPERATURE
Warning light TEMP
Priority light red
Audible indicator single chime sounded
¥ If the temperature rises to 127û C (260û F) or above, the fail safe strategy operates. At 127û C (260û F),
the EMS will cut out one cylinder (the selected cylinder is varied) and as the temperature continues
to rise, this will increase to a maximum of three cylinders cut (with cylinder cycling). The following
indications are given:
Temperature gauge pointer in red zone
Message Centre ENGINE POWER REDUCED
Warning light TEMP
Priority light red
Audible indicator three chimes sounded
¥ At 166û C (300û F) or above, the fail safe strategy continues as described but the following
indications are given:
Temperature gauge pointer in red zone
Message Centre PULL OFF ROAD SAFELY alternates with TURN OFF IGNITION
Warning light TEMP flashes
Priority light red
Audible indicator five chimes sounded
¥ EMS shuts the engine down.

V8 EngineAJ-V6/AJ28
49
Cooling System
The AJ28 engine retains the same basic cooling
system as the previous V8 engines but shares the
radiator, fan shroud assembly, de-gas circuit and
bottom hose oil cooler circulator features with the
V6. The coolant specified for the V6 is also
applicable to the V8 engine.
Particular features of the AJ28 cooling system are:
¥ The thermostat is located in the engine
mounted housing as in previous V8 engines.
¥ The thermostat housing is modified with an
extra stub pipe for the new heater returnhose.
¥ The throttle adaptor is heated from the main
cooling system to provide throttle de-icing.
¥ Both heater hoses, feed and return, are now
routed forward to the heater control valve.
¥ An electric pump is fitted in the heater
coolant circuit (ÔS-TYPE IntroductionÕ
Technical Guide).
¥ The coolant reservoir (de-gas bottle) is fitted
with a level sensor which provides a low level
warning on the instrument panel message
J.303.1366
V8 ENGINE COOLING SYSTEM
1. Radiator
2. Top hose
3. Bottom hose
4. Thermostat
5. Coolant pump6. Engine oil cooler
7. Reservoir bottle
8. Electronic throttle
9. V8 engine
10. AC/heater pump
110512
9
4
6
2
3
8
7
J.303.1365
11
13
11. Heater control valve
12. AC/heater unit
13. Bleed

V8 Engine AJ-V6/AJ28
50centre if the coolant level drops.
¥ The fail safe cooling strategy described for the
V6 is not applicable to the AJ28 engine.
Cooling System Hoses
The cooling system hoses are constructed of the
same materials and have the same type of fittings
as the V6 engine.
D.303.1370
J.303.1388
COOLING SYSTEM HOSES - TOP
J.303.1388
COOLING SYSTEM HOSES - FRONT
D.303.1370
Top Hose
Bottom Hose
A/C Heater
Pump
Heater Control
Valve
Engine Oil Cooler
To A/C Heater
Pump
Throttle
De-icing