Land Rover Defender V8i Workshop Supplement Rover Manual

							26 - COOLING SYSTEM
CONTENTS
Page
DESCRIPTION AND OPERATION
ENGINE COOLING 1..............................................................................................
COOLANT CIRCULATION 2...................................................................................
FAULT DIAGNOSIS
ENGINE OVERHEATING 1....................................................................................
ENGINE RUNS COLD 2.........................................................................................
ADJUSTMENT
COOLANT REQUIREMENTS 1..............................................................................
DRAIN AND REFILL 1............................................................................................
REPAIR
EXPANSION TANK 1..............................................................................................
VISCOUS COUPLING 1.........................................................................................
RADIATOR 3...........................................................................................................
THERMOSTAT 5.....................................................................................................
COOLANT PUMP 5.................................................................................................
SPECIFICATIONS, TORQUE
TORQUE VALUES 1............................................................................................... 
						

							COOLING SYSTEM
1
DESCRIPTION AND OPERATION ENGINE COOLING
Description
The V8i engine uses a pressurised cooling system
and cross flow radiator which is supplied from a
separate expansion tank. The coolant radiator also
incorporates a section at the side for cooling the
engine oil. The transmission fluid cooler is mounted
below the radiator.The belt driven viscous fan and centrifugal water
pump is located in the engine front cover with ports for
circulation of coolant to both banks of cylinders and
cylinder heads. Coolant returns to the top of the
radiator via ports in the inlet manifold where the
thermostat is mounted horizontally.
Coolant also circulates through the vehicle heating
system and is used to heat air entering the inlet
manifold plenum chamber.
Coolant circulation (engine hot)
1. Cross flow radiator
2. Expansion tank
3. Viscous fan and water pump
4. Heater pipes
5. Thermostat
6. Plenum chamber connection 
						

							26COOLING SYSTEM
2
DESCRIPTION AND OPERATION COOLANT CIRCULATION
Operation
When the engine is started from cold the thermostat
prevents any coolant circulation through the radiator
by closing off the top hose. During the engine warm
up period, the water pump, pumps coolant around the
cylinders to the rear of the cylinder block along the
main galleries in both cylinder banks. At the rear of
the cylinder block the coolant rises through a large
port in each cylinder head/block joint face, and then
flows forward to connect with ports at the front of the
inlet manifold. From the manifold the coolant is carried
by an external pipe to the heater unit and from the
heater through another external pipe to the pump
inlet.The coolant circulation through the cylinder block and
heads, does not change when normal running
temperature is reached and the thermostat opens. But
with the thermostat open, coolant also flows through
the top hose to the radiator where it is cooled and
drawn back into the pump via the bottom hose.
Throttle housing heating
The base of the throttle housing is heated by a flow of
coolant from the inlet manifold which returns through a
long hose, to the top right corner of the radiator. The
throttle housing is heated to prevent throttle disc icing. 
						

							COOLING SYSTEM
1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant Requirements
NO - Continue.
3.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
4.Are there any external leaks, from hoses,
coolant pump, engine gaskets or the heater unit?
YES - Investigate and rectify.
See Adjustment,
Coolant Requirements
NO - Continue.
5.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue.6.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous Coupling
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting
See Repair,
Thermostat
7.Is temperature sender and gauge giving
accurate readings?
NO - Substitute parts and compare readings.
YES - Continue.
8.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If the coolant only, or both systems are contaminated,
suspect cylinder head gaskets or radiator.
If only the lubrication stystem is contaminated with
coolant, suspect inlet manifold or front cover gaskets. 
						

							26COOLING SYSTEM
2
FAULT DIAGNOSIS ENGINE RUNS COLD
Before conducting any cooling system diagnosis:
See
Description and operation, Engine cooling
1.Check operation of viscous unit.See
Description and operation, Viscous Fan
Is viscous unit operating correctly?
NO -
See Repair, Viscous coupling
YES - Continue.
2.Is thermostat correct type and operating?
See
Repair, Thermostat
If problem is not diagnosed: Continue.
3.Are the air conditioning fans operating
continuously?
YES -
See Electrical Trouble Shooting
Manual.
NO - Continue.
4.Is temperature sender and gauge giving
accurate readings? Substitute parts and
compare readings. If problem is not diagnosed
repeat tests, starting at 1. 
						

							COOLING SYSTEM
1
ADJUSTMENT COOLANT REQUIREMENTS
Frost precautions and engine protection.
Cooling systemMUST ALWAYSbe filled and
topped-up with solution of water and anti-freeze,
winter and summer.NEVERuse water alone, this
may corrode aluminium alloy.
CAUTION: Do not use salt water otherwise
corrosion will occur. In certain territories
where only available natural water supply
has some salt content use only rain or distilled
water.
Recommended solutions
Anti-freeze:Universal anti-freeze or permanent type
ethylene base, without methanol, containing a suitable
inhibitor for aluminium engines and engine parts.
See
LUBRICANTS, FLUIDS AND CAPACITIES,
Information, Anti-freeze
Use one part of anti-freeze to one part of water.
Anti-freeze can remain in the cooling system and will
provide adequate protection for two years provided
that specific gravity of coolant is checked before onset
of second winter and topped-up with new anti-freeze
as required.
Vehicles leaving factory have cooling system filled
with 50% solution of anti-freeze and water. This gives
protection against frost down to minus 36°C, minus
33°F. Vehicles so filled are identified by a label affixed
to radiator.
NOTE: Should ambient temperatures be
below that stated above refer to
Anti-Freeze Data in Recommended
Lubricants, Fluids and Capacities in Section 09.
Instructions in chart must be strictly adhered to
before driving vehicle.
After the second winter the system should be drained
and thoroughly flushed. Before adding new anti-freeze
examine all joints and replace defective hoses to
make sure that the system is leak proof.
For protection quantities.
See LUBRICANTS,
FLUIDS AND CAPACITIES, Information,
anti-freeze
DRAIN AND REFILL
Service repair no - 26.10.01
Drain
WARNING: Do not remove expansion tank
filler cap when engine is hot. The cooling
system is pressurised and personal
scalding could result. See coolant requirements
before refilling system.
1.Remove expansion tank filler cap by slowly
turning it anti-clockwise. Pause to allow pressure
to escape. Continue turning it in same direction
and remove.
2.Remove viscous coupling.
See Repair,
viscous coupling
3.Remove radiator filler plug and O ring to assist
drainage. Discard O ring.
4.Position container to collect coolant spillage and
set heater controls to the HOT position.
5.Loosen clip securing hose to coolant pump.
6.Release hose from coolant pump and allow
coolant to drain. 
						

							26COOLING SYSTEM
2
ADJUSTMENT
NOTE: It is not possible to drain all coolant
retained in heater system.
7.Remove engine drain plugs beneath exhaust
manifolds and allow coolant to drain from
engine.
Refill
1.Fit drain plugs to engine.
2.Connect hose to coolant pump and secure with
clip.
3.Fit viscous coupling.
See Repair, viscous
coupling
4.Pour correct solution of water and anti-freeze
into expansion tank until radiator is full.
5.Start engine and run until normal operating
temperature is reached.
6.Top up coolant level as necessary.
7.Fit NEW O ring to radiator filler plug.
8.Fit radiator filler plug and tighten to
6Nm(4
lbf.ft).
9.Fit expansion tank filler cap.
10.Allow engine to cool and check coolant level.
11.Top-up expansion tank until level reaches seam.
12.Remove container. 
						

							COOLING SYSTEM
1
REPAIR EXPANSION TANK
Service repair no - 26.15.01
Remove
WARNING: Do not remove expansion tank
filler cap when engine is hot. The cooling
system is pressurised and personal
scalding could result.
1.Remove expansion tank filler cap by slowly
turning it anti-clockwise. Pause to allow pressure
to escape then continue to turn in same direction
and remove.
2.Position container to collect any coolant spillage.
3.Loosen clip securing radiator hose to expansion
tank.
4.Release radiator hose from expansion tank.
5.Loosen clip securing coolant hose to underside
of expansion tank.
6.Release coolant hose from expansion tank.
7.Remove overflow pipe from expansion tank.
8.Remove clamping bolt from expansion tank
mounting bracket and collect nut and washer.
9.Lift mounting bracket clamp and remove
expansion tank.
Refit
10.Fit expansion tank to mounting bracket.
11.Fit and tighten nut and bolt securing expansion
tank to mounting bracket.
12.Fit overflow pipe to expansion tank.
13.Connect coolant hose to underside of expansion
tank and secure with clip.
14.Connect radiator hose to expansion tank and
secure with clip.
15.Remove container.
16.Top-up engine coolant.VISCOUS COUPLING
Service repair no - 26.25.19
Remove
1.Disconnect battery negative lead and release
clips securing coolant hoses to fan upper cowl.
2.Remove 2 screws securing radiator top
mountings to fan upper cowl.
3.Release 2 clips securing fan upper cowl to lower
cowl.
4.Remove fan upper cowl.