The engine is cooled by the circulation of water
through the water jackets which surround the combustion chambers and
cylinders. The cooling water is circulated by the thermo-sypbon system. A
centrifugal type water pump which is located at the right hand side of the
cylinder block front, assists the thermo-syphon action.
The system is pressurised to operate at 7 lb/sq. in. (0,492 kg/sq. cm.) and is controlled by a spring-loaded rubber seal which
is fitted under the filling cap. The capacity of the system is 2,25
imperial gallons (18 pints. 11,6 litres or 2,6 U.S. gallons).
It is preferable that only soft water is used (c.g.
rainwater if available). When the engine is cold fill to approximately 1
inch from the top of the filler. Overheating may be caused through
improper carburettor adjustment, ignition too far retarded, excessive
carbon deposits in exhaust and inlet manifold, or insufficient water. To avoid the latter the water in
the radiator should be checked before undertaking long journeys.
A 7 P.S.I. Pressure Cap is fitted to the radiator
allowing the engine to be operated at slightly higher temperatures without
boiling. When removing the cap, turn slowly, or if the system is very hot allow to cool.
The forward mounted radiator is of the fin-and-tube
type. The filling cap is mounted high, on a curved tube extending upwards
and rearwards from the header tank. This is for ease of access above the
Conventional flexible flow and return hoses connect the
radiator and block. The top flow hose is shaped for offside entry at the
top front of the cylinder block.
REMOVING AND REPLACEMENT OF THE RADIATOR
Raise the bonnet lid, open drain tap, remove the
radiator filler cap and drain. If anti-freeze has been used, drain into a
clean container for re-use. Detach the top and bottom radiator hoses. The
top hose can be disconnected at the header
tank by removal of a jubilee clip and the bottom hose at the outlet pipe
at the cylinder block.
Unscrew three bolts securing the radiator to the
brackets which are attached to the front cross member.
The radiator can then be lifted out.
To replace the radiator, reverse the procedure detailed
In bad weather conditions (e.g. frost, low
temperatures) it is necessary to protect the cooling system from damage by
using anti-freeze mixture or by draining away all water.
A good proprietary make of anti-freeze should be used in accordance
with the manufacturers instructions. Salt and other substitutes should on
no account be used.
Glycerine or Ethylene-Glycol solutions are
satisfactory, and are readily availabie from Dealers. They must be mixed
with water in the recommended proportions.
The coolant inlet housing accommodates a
thermostatically controlled 'mushroom' valve, which opens to permit free
thermal circulation of the coolant fluid. This
opens at 80°C. (176°F.) The top coolant flow hose has a separate
thermostat, which controls an electrical switch wired to the fan motor.
The fan and motor are mounted immediately behind the radiator and the
control switch automatically cuts in at 85°C. (185°F.) and out at 75°C.
A temperature gauge is fitted to the instrument
dashboard, to the right, beneath the steering column. Normal operating
temperature is 85°C. (185°F.).
There is a drain cock beneath the radiator and one at
the rear offside of the cylinder block - just above the starter motor. The
filling cap should be removed to avoid risk of air-lock, when draining.
Periodic flushing of the system
is recommended and, if removed for overhaul, it is good practice to
reverse-flush the radiator and block when this is practicable.