Toyota
Dodge Durango
 Service Manual
Cooling System » Description and operation
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 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 Fig. 6 Radiator Pressure Cap-Typical

1 - FILLER NECK SEAL

2 - VACUUM VENT VALVE

3 - PRESSURE RATING

4 - PRESSURE VALVE

    More about «Description and operation»:

    Cooling system

    Coolant reserve/overflow system

    Thermostat-5.2L/5.9L engines

    Thermostat-4.7L engine

    Radiator pressure cap

    Radiator

    Water pump

    Water pump bypass-4.7L

    Water pump bypass hose-5.2L/5.9L engines

    Automatic transmission oil coolers

    Automatic belt tensioner

    Block heater

    Hose clamps

    Viscous fan drive

    Dodge Durango Service Manual / Cooling System / Description and operation / Radiator pressure cap

    Dodge Durango Service Manual

    Categories


    © 2017-2019 Copyright www.dodurango.net
    0.0024