Radiator Cap: Testing and Inspection

NOTE:
- If the radiator cap has contaminations, always rinse it with water.
- Before using a radiator cap tester, wet the relief valve and pressure valve with engine coolant or water.
- When performing steps below, keep the radiator pump tester at an angle of over 30° above the horizontal.

1. Using a suitable radiator cap pressure tester, slowly (1 push in 3 seconds or more) pump the tester and check that air is coming from the vacuum valve.

NOTE:
- Push the pump at a constant speed.
- If air is not coming from the vacuum valve, replace the radiator cap.

2. Pump the tester and measure the relief valve opening pressure

NOTE:
- Pump speed: 1 push within 1 second for the first pump only (in order to close the vacuum valve). After this, the pump speed can be reduced.
- Standard opening pressure:
74-103 kPa (10.7-14.9 psi)
- Minimum opening pressure:
59 kPa (8.5 psi)
- Use the tester's maximum reading as the opening pressure.
- If the opening pressure is less than minimum, replace the radiator cap.