Range Rover. Manual — part 124
LAND ROVER V8
11
DESCRIPTION AND OPERATION
Viscous unit engaged (hot running temperature)
Bi-metal coil expanded, valve open.
When the air temperature from the radiator drops
sufficiently, the bi-metal coil closes the valve and
prevents fluid entering the drive area, see 26M7026.
The fluid that is in the drive area will gradually pump
out into the reservoir and the fan will return to an idle
condition.
Engine oil cooler
The engine oil cooler is located in front of the radiator
above the gearbox oil cooler and comprises a single
row matrix; on 4.0 litre models three internal cooling
tubes are used; 4.6 litre models use a larger matrix
incorporating six cooling tubes. Pre-formed feed and
return pipes/hoses are used to link the cylinder block,
oil filter and oil cooler. The oil cooler is mounted
above the gearbox oil cooler, fixed to the radiator side
frame.
Oil drawn through a steel gauze strainer in the sump,
is pumped under pressure through the feed pipe into
the oil cooler. Ambient air, forced through the front
grille of the vehicle and assisted by the pull of the
viscous fan, is dispersed across the oil cooler. The
cooled oil then passes through the return pipe to the
filter, before being distributed from the cylinder block
to the various internal engine components.
Engine oil cooler - up to 99MY shown
1. Engine oil cooler
2. Feed pipe
3. Return pipe
4. Oil filter
5. Radiator
6. Gearbox oil cooler
26
COOLING SYSTEM
NEW RANGE ROVER
12
DESCRIPTION AND OPERATION
Gearbox oil cooler
The gearbox oil cooler is located below the engine oil
cooler in front of the radiator and comprises a single
row matrix. On vehicles fitted with manual gearboxes
three internal cooling tubes are used, on vehicles with
automatic transmission a larger matrix, incorporating
twelve coolant tubes is fitted. Pre-formed feed and
return pipes/hoses are used to link the gearbox and oil
cooler.
Oil is pumped under pressure from the gearbox
through the feed pipe into the oil cooler. Ambient air,
forced through the front grille of the vehicle and
assisted by the pull of the viscous fan, is dispersed
over the oil cooler. The cooled oil then passes through
the return pipe, which is routed under the engine to
run parallel with the feed pipe back to the LH side of
the gearbox.
Gearbox oil cooler - up to 99MY shown
1. Gearbox oil cooler
2. Feed pipe
3. Return pipe
4. Radiator
5. Engine oil cooler
LAND ROVER V8
1
FAULT DIAGNOSIS
COOLING SYSTEM FAULTS
This section covers mechanical faults that could occur
in the complete cooling system :
1. Engine (coolant) cooling;
2. Engine oil cooling;
3. Gearbox oil cooling.
Before conducting any visual checks within the
separate systems and undertaking detailed diagnosis
procedures.
See Description and operation.
1. ENGINE (COOLANT) COOLING SYSTEM
Symptom - Engine Overheating
POSSIBLE CAUSE
REMEDY
1. Engine coolant low.
1. Allow engine to cool. Top up expansion tank to correct level, with
engine running at idle. Check cooling system for leaks and rectify, if
necessary.
2. Loose drive belt.
2. Check/renew drive belt tensioner or renew drive belt.
See
ELECTRICAL, Repair.
3. Coolant in radiator frozen.
3. Slowly thaw and drain cooling system.
See Repair.
4. Air flow through radiator
restricted or blocked.
4. Apply air pressure to engine side of radiator to clear obstruction. If
mud or dirt is evident, carefully use a hose.
5. External leaks from water
pump, engine gaskets,
thermostat housing or
pipe/hoses.
5. Check for visual causes and rectify.
6. Viscous fan not operating
correctly or inoperative.
6. Renew viscous fan unit.
See Repair.
7. Thermostat seized in closed
position.
7. Check radiator bottom hose for coolant flow through radiator. If cold
a faulty thermostat is confirmed. Renew thermostat housing
assembly.
See Repair.
26
COOLING SYSTEM
NEW RANGE ROVER
2
FAULT DIAGNOSIS
Symptom - Engine Overheating, continued
POSSIBLE CAUSE
REMEDY
8. Air in cooling system.
8. Check coolant level. Run engine at fast idle (approximately 2,000
rpm) with expansion tank cap off. Top up coolant level with engine
at idle and refit expansion tank cap.
9. Air conditioning condenser fans
not operating correctly or
inoperative.
9.
See AIR CONDITIONING, Fault diagnosis.
10. Temperature gauge or sender
unit giving inaccurate readings.
10. Substitute parts and compare new readings.
11. Coolant leakage across
cylinder head gasket.
11. Carry out cylinder pressure test to determine if pressure is leaking
into cooling system, causing over pressurising and loss of coolant.
Renew cylinder head gasket.
12. Engine oil contamination of
cooling system due to leaking.
12. Renew cylinder head gasket.
See ENGINE, Repair.
13. Coolant contamination of
lubrication system.
13. Renew inlet manifold or front cover gaskets.
See MANIFOLD AND
EXHAUST SYSTEM, Repair. or See ENGINE, Repair.
Symptom - Engine Runs Cold
POSSIBLE CAUSE
REMEDY
1. Thermostat seized in open or
partially open position.
1. Remove thermostat housing and check operation of thermostat.
Renew, if necessary.
See Repair.
2. Temperature gauge or sender
unit giving inaccurate readings.
2. Substitute parts and compare new readings.
3. Viscous fan not operating
correctly.
3. Renew viscous fan unit.
See Repair.
4. Air conditioning condenser fans
operating continuously.
4. Refer to TestBook .
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