Page 928 of 2490
combin
ed with the outlet duct and consequently, there is no separate housin
g assembly fitted above the water pump, as used
on the normally aspirated engine. The illustration shows the outlet duct viewed from the engine.
Thermostat Housing
The plastic housing for the thermostat is fitted between th e two cylinder banks immediately above the coolant pump.
Controlling the coolant flow through the radiator, the thermostat starts to open at 80 ° to 84 °C and is fully open at 96 °C.
A duct in the cylinder block connects the thermostat housing outlet to the coolant pump inlet. The joint between the
thermostat housing and the cylinder block is via an in-groove seal.
An air bleed outlet vents an y air in the system into the expansion reservoir, durin
g normal operation. A removable cap (usin g
a hex key) allows air to vent from the system when filling from empty.
On supercharged engines, the thermostat housin g is combined with the coolant outlet duct.
Radiator
Page 956 of 2490

• NOTE
: To ensure that
air is not drawn into the system during the following operations:
Do
not remove the cap from the header tank whilst the
charge air cooling system is open to atmosphere.
Do
not switch on the ignition when th
e charge air cooling system is open to atmosphere because the electrical
cooling pump may draw air into the system.
2. Fi
ll the cooling system at the header tank until the
level stabilises near the to p of the charge air cooler
fill point. This will take some time, as air is being
purged from the system.
Ensure that the head
er tank is full.
2. Fit the pressure cap to the header tank.
3. Pour coolant careful l
y into the charge air cooler fill point until
the system is full.
Fi t t
he plug and washer to the fill point.
4. Remove the pressure cap from the header tank.
5. Switch on the ignition and switch off the climate control
system.
Le ave
the ignition switched on (do not start the engine)
for at least 2 minutes to allow the air charge cooler
electric water pump to oper ate and to purge any air from
the air charge cooler radiator to the header tank. (This
operation will be repeated later)
6. Switch off the ignition for at least 1 minute.
7. Leave the ignition switched on (do not start the engine) for at
least 2 minutes to allow the air charge cooler electric water
pump to operate and to purg e any air from the air charge
cooler radiator to the header tank.
8. Top up the cooling system.
1. Top up the header tank and fit the pressure cap.
2. Remove the plug from the air charge cooler fill point. Pour coolant carefully into the air charge cooler fill
point until the system is full.
3. Fit the plug and washer to the fill point.
Page 962 of 2490

All vehicles
21.
N
OTE: Install a new sealing washer.
• NOTE: Clean off any spillages.
Install the supercharger coolant fill plug.
Tighte
n to 45 Nm.
22. Remove the coolant expans ion tank pressure cap.
23. Switch ignition on.
24. CAUTION: Do not allow the supercharger water pump to
run dry. Failure to follow this instruction may result in damage to
the vehicle.
• NOTE: Leave the ignition switched on (do not start the engine)
for at least 2 minutes to allow the air charge cooler electric water
pump to operate and to purge an y air from the air charge cooler
radiator to the header tank.
Allow the supercharger pump to run and top up the system
through the coolant expansion tank.
25 . Swit
ch the ignition off.
26. Install the coolant expansion tank pressure cap.
27. START and RUN the engine.
28. CAUTION: Observe the engine temperature gauge. If
the engine starts to over-heat switch off immediately and allow to
cool. Failure to follow this inst ruction may cause damage to the
vehicle.
Run the engine at between 1500 and 2000 rpm until the cooling
fan operates.
29 .
Swi
tch off the engine.
30. Allow the engine to cool.
31. Check and top-up the coolant if required.
Page 1001 of 2490

Engine Cooling - Water Pump4.0L NA V8 - AJ27/ 3.2L NA V8 - AJ26
Re
moval and Installation
Remov
al
1.
O
pen the engine compartment and fit paintwork protection
sheets.
2. Drain the cooling system.
For additional information, refer to Cooling System Draining,
Fillin
g and Bleeding
- Vehicles W
ithout: Supercharger
in
this
section.
3. Sl
acken the three screws which
secure the water pump pulley.
4. CAUTI
ON: When releasing the
belt tension, never apply
any torque in a clockwise direction to the pulley ce ntre bolt (left
hand thread) as it could subsequently loosen.
Remove the drive belt from the generator and accessory drive.
1. Use a spanner e.g. Churchill JD-230 or Snap On XDHM 1415, on the centre bo lt of the belt tensioner
idler pulley, to turn the adju ster assembly to the left
against spring tension.
2. Whilst holding the tensioner against spring tension, remove the drive belt from the generator pulley.
Release the tensioner sl owly and remove the
spanner.
D
isconnect the belt from the ot
her pulleys, as necessary,
to move it clear of the pump pulley.
5. Re
move the pulley from the water pump.
1. Remove the pulley securing screws.
2. Remove the pulley from the water pump.
6. Remove the water pump.
1. Remove the five bolts wh ich secure the water pump.
Page 1002 of 2490
In
stallation
2.
Remove the water pump from the engine.
7. Remo
ve the gasket.
1. Remove and discard the water pump gasket.
2. Remove and discard the water pump O-ring seal.
8. Clean any coolant spillage fro m the engine compartment.
9. Clean all relevant part s and sealing faces.
1. To i
nstall, reverse the removal procedure.
Install a new water
pu
mp gasket and O-ring seal.
2. Tigh ten th
e water pump bolts to 8 Nm + 90°.
3. Tighten the water pump pulley bolts to 10-14 Nm.
Page 1004 of 2490

Engine Cooling - Water Pump4.0L SC V8 - AJ26
Remo
val and Installation
Remov
a
l
1.
Op
en the engine compartment and fit paintwork protection
sheets.
2. Drain the cooling system.
For additional information, refer to Cooling System Draining,
Filling and Bleedin
g
- Vehicles With
: Supercharger in this
section.
3. Remove the supercharger driv e belt. Refer to Operation
18.50.08.
4. Slacken the three screws whi
ch
secure the water pump pulley.
5. CAUTIO
N: When releasing the
belt tension, never apply
any torque in a clockwise direction to the pulley ce ntre bolt (left
hand thread) as it could subsequently loosen.
Remove the drive belt from the generator and accessory drive.
1. Use a spanner e.g. Churchill JD-230 or Snap On XDHM 1415, on the centre bo lt of the belt tensioner
idler pulley, to turn the adju ster assembly to the left
against spring tension.
2. Whilst holding the tensioner against spring tension, remove the drive belt from the generator pulley.
Release the tensioner sl owly and remove the
spanner.
Di
sconnect the belt from the ot
her pulleys, as necessary,
to move it clear of the pump pulley.
6. Remove t
he pulley from the water pump.
1. Remove the pulley securing screws.
2. Remove the pulley from the water pump.
7. Remove the water pump.
Page 1005 of 2490
I
nstallation
1
. Remove the five bolts wh
ich secure the water pump.
2. Remove the water pump from the engine.
8. Re
move the gasket.
1. Remove and discard the water pump gasket.
2. Remove and discard the water pump O-ring seal.
9. Clean any coolant spillage fro m the engine compartment.
10. Clean all relevant part s and sealing faces.
1. To
install, reverse the removal procedure.
Install a new water
pump gasket and O-ring seal.
2. Tigh
ten the water pu
mp securing bolts to 8 Nm + 90°.
3. Tighten the water pump pulley bolts to 10-14 Nm.
Page 1007 of 2490
W
ater Pump Pulley Vehicles Without: Supercharger
26.50.05
Removal
1. Open the engine compartment and fit paintwork protection sheets.
2
. Slacken the three screws which secure the water pump pulley.
3
.
C
AUTION:
When releasing the belt tension, never apply any torque in a clockwise direction to the pulley
centre bolt (left hand thread) as it could subsequently loosen.
Remove the drive belt from the generator and accessory drive. 1. Use a spanner e.g. Churchill JD-230 or Snap On XDHM 1415, on the centre bolt of the belt tensioner idler pulley, to turn the adjuster assembly to the left against spring tension.