Cooling system (Operation): Description and operation

Operation

The cooling system employed is the bypass type.

When the engine is cold the thermostat closes off the coolant feed from the radiator bottom hose (1). Coolant in the cylinder head and heater matrix (2) begins to rise in temperature after the engine is started. The heater is regulated by a control valve (3) from the dashboard. Coolant circulates back into the heater circuit through a by-pass hose (4) prior to the thermostat opening.

As temperature increases the thermostat (5) gradually opens, allowing hot coolant to flow to the radiator (6) via the top hose (7). As the thermostat opens further so the full flow of coolant is drawn through the radiator.

Any excess coolant created by heat expansion is returned to the expansion tank (8) via hose (9).

The radiator is an aluminium cross-flow type with integral end tanks and is mounted on rubber bushes directly into the subframe transverse member. The top of the radiator is supported by means of mounting brackets bolted to the radiator and bonnet locking platform.

For additional air flow, at times when the vehicle is stationary, an electric cooling fan is fitted. It is triggered by the Engine Control Module (ECM).

The coolant pump (10) is a rotor type pump which draws coolant directly from the radiator. The pump is driven by a poly-V pulley from the alternator drive belt.