Components of a Cooling System

Inlet tank

Coolant enters radiator here via a hose.

Core

Coolant passes through water tubes where heat is removed via cooling fins and air passing through the core matrix.

Outlet tank

Coolant collects here, then leaves radiator and passes back to engine via a hose. Automatic cars usually have an oil cooler in the outlet tank.

Water pump

Pumps the coolant through the cooling system maintaining a velocity suitable for heat transfer.

Fan &
Shroud

Attached to the radiator to ensure air flow even when stationary. Initially mechanically powered, fans are now electrically powered for most applications.

Coolant

A mixture of specific chemical additives & demineralised water to prevent freezing, increase the boiling point & prevent corrosion of the cooling system. It transfers the heat from the engine to the atmosphere via the radiator. The recommended coolant must be used.

Overflow Reservoir

Plastic container that contains extra coolant for the radiator and provides a place for overflow to pass to while still remaining in the system. Extra liquid should be added here when required.

Thermostat Valve

Assists the engine to quickly reach and maintain the proper temperature by shutting when the coolant is cold, allowing it to first heat up in the engine.

Radiator Pressure Cap

At the top of the radiator or overflow reservoir. Allows the system to operate under pressure which increases the coolant boiling temperature. Do not open when hot. Has two valves - a pressure valve and a vacuum valve.

Heater Core (Assy)

Heats passenger compartment.