Radiator pressure cap. Radiator

Radiator pressure cap

DESCRIPTION

All radiators are equipped with a pressure cap.

This cap releases pressure at some point within a range of 124-to-145 kPa (18-to-21 psi). The pressure relief point (in pounds) is engraved on top of the cap 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 springloaded pressure relief valve. This valve opens when system pressure reaches the release range of 124-to- 145 kPa (18-to-21 psi).

A rubber gasket seals the radiator filler neck. This is done to maintain vacuum during coolant cool-down and to prevent leakage when system is under pressure.

Fig. 5 Thermostat Cross Section View 4.7L

1 - FROM HEATER

2 - FROM RADIATOR

3 - TO WATER PUMP

4 - ENGINE BYPASS

5 - THERMOSTAT

OPERATION

A vent valve in the center of the cap will remain shut as long as the cooling system is pressurized. As the coolant cools, it contracts and creates a vacuum in cooling system. This causes the vacuum valve to open and coolant in reserve/overflow tank to be drawn through connecting hose into radiator. If the vacuum valve is stuck shut, or overflow hose is kinked, radiator hoses will collapse on cool-down.

Fig. 6 Radiator Pressure Cap-Typical

1 - FILLER NECK SEAL

2 - VACUUM VENT VALVE

3 - PRESSURE RATING

4 - PRESSURE VALVE

Radiator

DESCRIPTION

The radiator is a aluminum cross-flow design with horizontal tubes through the radiator core and vertical plastic side tanks.

OPERATION

The radiator supplies sufficient heat transfer using the cooling fins interlaced between the horizontal tubes in the radaitor core to cool the engine and automatic transmission oil (if equipped).