Radiator Pressure Cap Inspection

Fig 1: Identifying Radiator Pressure Cap Inspection

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

1 - OVERFLOW NIPPLE

2 - MAIN SPRING

3 - GASKET RETAINER

4 - STAINLESS-STEEL SWIVEL TOP

5 - RUBBER SEALS

6 - VENT VALVE

7 - RADIATOR

8 - FILLER NECK

Use only a mild soap to clean the pressure cap (4).

Hold the cap in your hand, >>top side up<<. The vent valve at the bottom of the cap should open. If the rubber gasket has swollen, preventing the valve from opening, replace the cap.

Hold the cleaned cap in your hand, >>upside down.<< If any light can be seen between vent valve and the rubber gasket, replace the cap. >>Do not use a replacement cap that has a spring to hold the vent shut.<<

A replacement cap must be of the type designed for coolant reserve systems. This design ensures coolant return to the radiator.