1 General information and
precautions
The cooling system is of the conventional
pressurised, water pump-assisted thermo-
syphon type comprising a radiator, water
pump, thermostat and associated hoses.
Radiator cooling is provided by a fan mounted
on the water pump and driven by a V-belt from
the crankshaft pulley. An auxiliary electric
cooling fan is fitted to later 1275 cc engine
models. It is located beneath the left-hand front
wheel arch, and provides an additional source
of cooling for the radiator in conjunction with
the belt-driven fan on the water pump.
The cooling system functions by circulating
cold coolant from the bottom of the radiator,
up the lower radiator hose to the water pump
where it is pumped around the water
passages in the cylinder block.
The coolant then travels up into the cylinder
head and circulates around the combustion
chambers and valve seats. When the engine is
at its correct operating temperature, the coolant
travels out of the cylinder head, past the open
thermostat, into the hose and so into the top
tank of the radiator. The coolant travels down
the radiator where it is rapidly cooled by the
rush of cold air through the radiator core. As the
radiator is mounted next to the wheel arch, the
fan pushes cold air through the radiator matrix.
The coolant, now cool, reaches the bottom of
the radiator where the cycle is repeated.
When the engine is cold, the thermostat
(which is simply a temperature sensitive
valve), maintains the circulation of coolant in
the engine by blocking the passage from the
cylinder head to the radiator. The coolant is
then forced to return to the cylinder block
through the bypass hose. Only when the
opening temperature of the thermostat has
been reached, does the thermostat allow the
coolant to return to the radiator.
A basic heating and ventilation system is
fitted which supplies warm or cold air to either
the windscreen or car interior. A two-speed
blower fan is fitted to supplement the airflow
as required. Fresh air ventilation is provided
by controllable air vents, located below the
windscreen on each side of the car. These
vents are independent of the main
heater/blower unit and provide ambient air
when the car is moving. The volume of air
supplied is dependent on road speed.
Precautions
Warning: Do not attempt to
remove the radiator filler cap, or
to disturb any part of the cooling
system, while it or the engine is
hot, as there is a very great risk of scalding.
If the filler cap must be removed before the
engine and radiator have fully cooled down
(even though this is not recommended) the
pressure in the cooling system must first
be released. Cover the cap with a thick
layer of cloth, to avoid scalding, and slowly
unscrew the filler cap until a hissing sound
can be heard. When the hissing has
stopped, showing that pressure is
released, slowly unscrew the filler cap
further until it can be removed; if more
hissing sounds are heard, wait until they
have stopped before unscrewing the cap
completely. At all times, keep well away
from the filler opening.
Warning: Do not allow antifreeze
to come in contact with your
skin, or with the painted
surfaces of the vehicle. Rinse off
spills immediately with plenty of water.
Never leave antifreeze lying around in an
open container, or in a puddle in the
driveway or on the garage floor. Children
and pets are attracted by its sweet smell,
but antifreeze is fatal if ingested.
2 Cooling system hoses -
disconnection and renewal
1
Note: Refer to the warnings given in Section 1
of this Chapter before proceeding. Hoses
should only be disconnected once the engine
has cooled sufficiently to avoid scalding.
1 If the checks described in Chapter 1 reveal
a faulty hose, it must be renewed as follows.
2 First drain the cooling system (Chapter 1); if
the antifreeze is not due for renewal, the
drained coolant may be re-used, if it is
collected in a clean container.
3 To disconnect the main system hoses, use a
pair of pliers to release the spring clamps (or a
screwdriver to slacken screw-type clamps),
then move them along the hose clear of the
union. Carefully work the hose off its stubs. The
hoses can be removed with relative ease when
new - on an older vehicle, they may have stuck.
4 If a hose proves to be difficult to remove, try
to release it by rotating it on its unions before
attempting to work it off. Gently prise the end
of the hose with a blunt instrument (such as a
flat-bladed screwdriver), but do not apply too
much force, and take care not to damage the
pipe stubs or hoses. Note in particular that the
radiator hose unions are fragile; do not use
excessive force when attempting to remove
the hoses.
5 When refitting a hose, first slide the clamps
onto the hose, then engage the hose with its
unions. Work the hose into position, then
check that the hose is settled correctly and is
properly routed. Slide each clip along the
hose until it is behind the union flared end,
before tightening it securely.
6 Renewal of the by-pass hose (fitted
between the top of the water pump and the
underside of the cylinder head) is an awkward
and tedious task which often presents
problems. The easiest way to refit a bypass
hose is to first place both clips in position on
the hose. Fit the bottom of the hose to the
water pump, bend the hose in half and then
place the flat faces of a knife or feeler blade
over the top of the hose and outlet in the
cylinder head. Push the hose into an upright
position and withdraw the blade. The hose
should now be in position over the outlet.
Several attempts may be necessary before
the hose slides properly into position.
7 Refill the system with coolant (Chapter 1).
8 Check carefully for leaks as soon as
possible after disturbing any part of the
cooling system.
3 Antifreeze - general
information
Note: Refer to the warnings given in Section 1
of this Chapter before proceeding.
1 The cooling system should be filled with a
water/ethylene glycol-based antifreeze
solution, of a strength which will prevent
freezing down to at least -25ºC, or lower if the
local climate requires it. Antifreeze also
provides protection against corrosion, and
increases the coolant boiling point. As with all
mixed metal engines, the corrosion protection
properties of the antifreeze are critical. Only a
top quality antifreeze should be used in the
system and should never be mixed with
different antifreeze types.
2 The cooling system should be maintained
according to the schedule described in
Chapter 1. If antifreeze is used that is not to
Rover’s specification, old or contaminated
coolant mixtures are likely to cause damage,
and encourage the formation of corrosion and
scale in the system.
3 Before adding antifreeze, check all hoses
and hose connections, because antifreeze
tends to leak through very small openings.
Engines don’t normally consume coolant, so if
the level goes down, find the cause and
correct it.
4 Ideally, at least a 30% mixture of antifreeze
and clean soft water (by volume) should be
used to maintain maximum protection against
freezing and corrosion. Mix the required
quantity in a clean container and then fill the
system as described in Chapter 1, and
“Weekly Checks”. Save any surplus mixture
for topping-up.
3•2 Cooling, heating and ventilation systems
If all else fails, cut the hose
with a sharp knife, then slit it
so that it can be peeled off in
two pieces. Although this
may prove expensive if the hose is
otherwise undamaged, it is preferable
to buying a new radiator.
If the hose is stiff, use a little
soapy water as a lubricant,
or soften the hose by
soaking it in hot water. Do
not use oil or grease, which may attack
the rubber.
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