Owners Manual
AUSTIN
A40
SERVICE
MANUAL
B/l
COOLING SYSTEM
AN
efficient cooling system
is
of
major importance to ensure the satisfactory running
of
the engine and
it
is therefore
necessary to pay particular attention to its maintenance. Attention is especially drawn to the procedure advised
for the winter months,
if
damage to the unit is to be avoided.
Description
The cooling system is maintained
by
water pump
circulation combined with an efficient fan-cooled
radiator and thermostat.
The radiator incorporates an expansion chamber,
which prevents the loss
of
water. When under operation
the cooling water expands and rises, thus filling the
expansion chamber.
Fig. 1. The cooling system.
A.
Heater
pipes.
B.
Filler
cap. C. Thermostat.
D.
By-pass pipe. E.
Water
pump.
F.
Radiator
bottom
tank.
G.
Radiator
drain
tap.
H.
Cylinder
block
drain
tap. J.
Control
valve (Sports
and
Com-
mercial vehicles only).
The displaced air resulting from this, escapes
through a small overflow pipe connecting the top
of
the
chamber with the bottom
of
the filler plug well. Should
any further expansion take place, the water
flows
along
this overflow pipe to the filler plug well, being drawn
back into the radiator when the engine cools.
Topping up is only necessary very occasionally,
to replace water lost through evaporation.
Use only
rain water
if
available, or alternatively clean, soft water,
and
fill
to just below the
top
of
the filler plug thread
Fig. 2.
The
radiator
filler,
and
expansion system.
A. Overflow cap. B. Overflow pipe. C. Filler cap.
D.
Filler cap well.
when the engine is cold. The total capacity
of
the
cooling system
is
12
pints (Saloon) and
14
pints (Sports).
Thermostat
In
order to ensure maximum engine efficiency, it is
essential to keep the engine operating temperatures
within certain limits. To assist this, a Smith's bellows
thermostat is fitted, being located in the water outlet at
the front
of
the cylinder head. The device consists
of
metallic bellows, filled with a volatile liquid, which
control a mushroom valve. When the engine is cold
this valve is closed, a by-pass being fitted
to
allow for
slight circulation.
On starting the engine the flow
of
water to the radiator will be temporarily restricted. Due
to this the temperature
of
the water in the cylinder
jackets will quickly rise, thus ensuring rapid warming up.
The heat
so
generated will gradually expand the bellows
so opening the valve, and ultimately permitting full flow
to the radiator.
The thermostat itself is detachable; therefore,
should occasion arise,
it
can be removed from its housing
and the hose reconnected
to
avoid laying up the car.
Should the thermostat be tight there are two tapped
holes on the top which may be utilised to ease it from the
casting.
When the system has been completely emptied,
it
is essential to wait a minute or two after refilling to
allow air to escape through the thermostat valve and
then finally top up.