General Cooling System Servicing: Description

The basic liquid cooling system consists of a radiator, water pump, thermostat, cooling fan, pressure cap, heater, if equipped, and various connecting hoses and cooling passages in the block and cylinder head. In addition, many cars use a fan clutch, which may incorporate a thermostatic control, or a flexible blade fan, or both, to reduce noise and power requirements at high engine speeds. Some models, with exhaust emission control, use a thermostatic vacuum switch to advance ignition timing in the event of overheating. As most new models require the use of a permanent, year round (ethylene glycol) type antifreeze, coolant recovery systems are being used more commonly to prevent coolant loss.