Series
Land Rover Cooling System
- Fault Diagnosis
Outline
of the cooling system
operation.
The cooling system in
a Series Land Rover begins
to operate once the engine
coolant has reached approximately
75C. At about this temperature
the thermostat, located
in the cylinderhead below
the top radiator hose,
begins to open. At about
90C the thermostat is
fully open and coolant
can circulate freely.
Coolant is pumped by the
mechanical water pump
from the bottom of the
radiator into the engine
block. From here it circulates
around the block and cylinderhead
and then enters the radiator
through the top radiator
hose.
The fan and motion of
the Land Rover both draw
air through the radiator
and cool the coolant in
the process.
In cold climates the coolant
is a mixture of water
and antifreeze whereas
in tropical climates
the coolant may consist
entirely of a commercial
coolant mixture.
The coolant is under pressure
so that the boiling point
of the coolant is raised
above its normal value.
A Series Land Rover is
often called upon to provide
a power source whilst
stationary and
it is for this reason
that a large capacity
radiator and cooling fan
is provided. If the vehicle
is not used in a tropical
environment and maintains
reasonable forward movement
than the fan is often
not required. In these
circumstances a temperature
controlled electric fan
could be utilised with
slight gain in fuel consumption
as a result.
Leakage
External
- Clips
on
top, bottom or bypass
hoses not fully tightened;
perished
water hoses; gaskets
on engine components leaking
due to components not
being fully tightened
e.g.water pump seals;
thermostat gasket; loose
or damaged core plugs;
damaged radiator seams,
drain tap not fully tightened;
spring in the radiator
filler cap weak or the
seal for the cap not sealing.
Internal - Damaged
head gasket
causing water to enter
cylinders and/or oil (coolant
may also be pushed down
the overflow pipe under
pressure);
loose cylinder head bolts;
cracked cylinder bore
or cylinder head.
Poor
Circulation
Squashed
or internally collapsedwater
hose; not enough coolant
in the system; loose and
slipping fan belt; thermostat
not opening fully;
faulty water pump;
blockage in the radiator
core;
Corrosion
Lack
of regular flushing and
draining of coolant; incorrect
coolant used; excessively
polluted water used.
Overheating
Engine faults:
Blocked thermosat;
faulty water pump.
carburettor mixture too
weak (P); blown cylinder
head gasket; low oil level
or dirty oil (blocking
oil galleries); fuel distributor
pump setting wrong (D);
ignition timing wrong
(P); distributor
advance and retard mechanism
not set correctly (P);
valve
timing wrong; new engine
not yet run-in.
Other
causes:
Insufficient
or incorrect coolant used;
insufficient draining
and flushing of system
causing corrosion deposits
to accumulate;
water
hose collapsed;
air
lock in cooling system
(usually at the heater);
air flow through radiator
restricted;
partially blocked exhaust
pipe or silencer; binding
brakes; vehicle overloaded,
excessive hill climbing,
low gear work or idling;
Overcooling
Thermostat
stuck open or missing;
wrong thermostat fitted
for the particular working
environment of the Land
Rover; inaccurate temperature
guage.
or 
sections 
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