oil level JAGUAR S TYPE 1999 1.G Powertrain Manual

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

Manual Transmission AJ-V6/AJ28
66With a conventional clutch, increased lining wear
causes the angle of the actuating diaphragm
spring to change as the pressure plate moves
axially towards the engine, requiring a greater
force to operate the clutch (diaphragm actuating
force varies with diaphragm angle). The self
adjusting clutch eliminates the problem by
allowing the diaphragm spring to follow the axial
movement of the pressure plate thus maintaining
the diaphragm spring at the same angle
throughout the life of the clutch. As well as
maintaining a constant pedal pressure, the clamp
force on the pressure plate also remains constant
with wear.
The operation is shown in the diagram. The
diaphragm spring is not fixed at its rotation point
like the conventional system but pivots between a
sensor spring and an adjuster ring. The sensor
spring provides a counter force which is just
sufficient to retain the diaphragm spring axially
against the cover via the adjuster ring and during
normal actuation of the clutch. As the linings
wear, the tendency of the diaphragm angle to
change causes an increase in the actuation force
required to operate the clutch. When this
increased effort exceeds the counter force of the
sensor spring, the diaphragm spring moves axially
towards the pressure plate until the original angle
is restored. At this point the actuation force
required drops to the level of the opposing sensor
spring force, restoring equilibrium with the
diaphragm spring at its new location.
During the axial movement of the diaphragm
spring, the increased distance between the spring
and cover is taken up by the adjuster ring. This
ring has fifteen raised segments, each having a
ramp profile which fits into a corresponding
shape in the clutch cover. When the diaphragm
spring moves axially for wear compensation,
three pre-loaded coil springs in the clutch cover
cause the adjuster ring to rotate, moving up the
ramps and taking up the extra distance between
the diaphragm spring and clutch cover.
Note that, in operation, the adjuster ring rotates
in a clockwise direction, as viewed from the
transmission. If a worn driven plate is replaced in
service and the clutch cover assembly is to be re-
used, the adjuster ring must be rotated back to its
pre-loaded position (see JTIS service instructions).
J.307.318
DUAL MASS FLYWHEEL AND CLUTCH ASSEMBLY
J.307.318
J.307.319
OPERATION OF SELF ADJUSTING CLUTCH
J.307.319
Dual Mass
Flywheel
Assembly
Self Adjusting
Clutch
Driven Plate
Concentric
Slave Cylinder
Adjuster
Ring
Conventional
Clutch
Sensor Spring
Diaphragm
Spring
Self Adjusting
Clutch
Diaphragm
Spring