Description and maintenance

Cooling and heating systems / Description and maintenance

1 The cooling system consists of a front-mounted radiator with built-in expansion tank, a coolant pump (belt-driven from the crankshaft pulley) and a thermostaticallycontrolled electric cooling fan.

2 In order to assist rapid warm-up, a thermostat is located in a housing at the left-hand end of the cylinder head. The hose connections to the thermostat housing vary according to model.

3 The heater is supplied with coolant from the engine and incorporates a matrix and blower with the necessary controls.

4 The throttle valve plate block of the carburettor is coolant-heated as a means of improving fuel atomisation.

5 Maintenance is minimal as in theory no coolant should ever be lost from the expansion tank. Regularly check that the coolant level is between 50.0 and 70.0 mm (1.97 and 2.8 in) above the MIN mark on the tank with the engine cold. The need for regular topping up will indicate a leak somewhere in the system. If one cannot be found suspect an internal leak in the engine although this is usually confirmed by a rise in the engine oil level and water on the dipstick (photo). Any topping-up should be done using an antifreeze mixture (see Section 3), not plain water.

1.5 Expansion tank cap

6 Avoid unscrewing the expansion tank cap when the engine is hot, but if this must be done, cover the cap with a cloth to avoid scalding by escaping steam.

7 Periodically, check the condition of all coolant hoses and tighten the clips.

Fig. 2.1 Cooling system on 903 cc engine (Sec 1)