Jaguar AJV8 engine / 5HP24 transmission. Manual - part 4

Engine

AJ-V8/5HP24

17

Engine Cooling

The cooling system is a low volume, high velocity
system with good warm-up and temperature
profile characteristics. 
From the pump, the coolant flows into each bank
of the cylinder block. In each bank, 50% of the
coolant cools the cylinder bores and 50% is
diverted through a bypass gallery. At the rear of
the banks the two flows mix and enter the
cylinder heads. The coolant then flows forwards
to the outlet ports. When the thermostat is
closed, the coolant returns directly to the pump
through the bypass on the thermostat housing.
When the thermostat is open, the coolant returns
to the pump via the vehicle's radiator.
A coolant drain plug is installed on the rear left
side of the cylinder block. On vehicles with the
cold climate package, the cylinder block heater
replaces the drain plug.

Note:  Coolant is drained from the right bank of

the cylinder block by removing the
coolant pipe behind the starter motor.

CYLINDER BLOCK DRAIN/HEATER

COOLING SYSTEM DIAGRAM

1.

Electronic Throttle

2.

EGR Valve

3.

A/C Heater Return

4.

Coolant Pump

5.

Thermostat Housing

6.

Vehicle Radiator (Reference)

7.

A/C Heater Supply

8.

Bleed Outlet

8

1

2

3

4

7

6

5

303-O63

303-028

Engine

AJ-V8/5HP24

18

Coolant Pump

The coolant pump is installed between the two
cylinder banks, on the front face of the cylinder
block. The pumping element is a shrouded
composite impeller. Coolant escapes from seal
breather holes in the housing if the pump's
bearing seal fails.
An O-ring and an edge bonded rubber/aluminum
alloy gasket seal the pump to cylinder block
interface. The O-ring seals the inlet port from the
thermostat. The gasket seals the outlet ports into
the cylinder banks.

Thermostat Housing

The composite thermostat housing is installed
between the two cylinder banks, immediately
above the coolant pump. The thermostat controls
the flow of coolant through the radiator. It starts
to open at 80 to 84°C (176 to 183˚F) and is fully
open at 96°C (205˚F).
A duct in the cylinder block connects the
thermostat housing outlet to the pump inlet. A
stub pipe connects the duct to the air conditioning
heater matrix return line.
An in-groove gasket seals the joint between the
thermostat housing and the cylinder block.
In addition to containing the thermostat, the
composite thermostat housing incorporates
connections for the bleed, bypass and radiator
bottom hoses. The bleed outlet vents any air in
the system into the vehicle's coolant reservoir.
The cap of the thermostat housing is removable,
to allow air out of the system when filling from
empty.

CAUTION: Use the correct torque (marked on

the cap) when re-installing the
cap, or the cap/thermostat
housing could be damaged.

COOLANT PUMP

303-030

THERMOSTAT HOUSING

Coolant Hoses

Supply and return hoses for the air conditioning
heater matrix are installed between the cylinder
banks.
A connection at the rear of A bank provides the
coolant supply for the electronic throttle and the
EGR valve. The outlet from the EGR valve
connects to the return hose of the air conditioning
heater matrix.

By-pass

From
Radiator

A/C Heater
Return

Cap

Bleed

303-029

Engine

AJ-V8/5HP24

19

COOLANT HOSES

A/C Heater Matrix

303-032

Electronic Throttle

EGR Valve

Electronic Throttle

Engine

AJ-V8/5HP24

20

Engine Lubrication

Oil is drawn from the reservoir in the oil pan and
pressurised by the oil pump. The output from the
oil pump is then filtered and distributed through
internal oil passages.
All moving parts are lubricated by pressure or
splash oil. Pressurised oil is also provided for
operation of the variable valve timing units and
the timing gear chain tensioners.
The oil returns to the oil pan under gravity. Large
drain holes through the cylinder heads and
cylinder block ensure the quick return of the oil,
reducing the volume of oil required and enabling
an accurate check of the contents soon after the
engine stops.
System replenishment is through the oil filler cap
on the B bank camshaft cover.
With the exception of the pump and level gauge,
all oil system components are installed on the
structural sump.

Coolant Outlet Duct

The composite coolant outlet duct connects to
the outlet port of each cylinder head to provide a
common connection point for the radiator top
hose. It also incorporates connections for the
coolant temperature sensor, the supply to the air
conditioning heater matrix, and the bypass flow
to the thermostat housing.
An in-groove gasket seals each of the joints
between the outlet duct and the cylinder heads.

COOLANT OUTLET DUCT

ECT Sensor

A/C Heater
Supply

By-pass

To Radiator

303-066