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 vehicles us 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 use of a permanent, year-round (ethylene glycol) type anti-freeze, coolant recovery systems are being used more commonly to prevent coolant loss.