Cap, Radiator: Description
All cooling systems are equipped with a pressure cap on the pressurized coolant bottle. This cap releases pressure at some point within a range of 110-144 kPa (16-21 psi). The pressure relief point (in pounds) is engraved on top of the cap (3).
The cooling system will operate at pressures slightly above atmospheric pressure. This results in a higher coolant boiling point allowing increased radiator cooling capacity. The cap contains a spring-loaded pressure relief valve (2). This valve opens when system pressure reaches the release range of 110-144 kPa (16-21 psi).
A rubber gasket (1) and (4) seals the pressurized bottle filler neck. This is done to maintain vacuum during coolant cool-down and to prevent leakage when system is under pressure.