Radiator Cap: Testing and Inspection

1. Remove radiator cap from reservoir tank.

WARNING: To avoid the danger of being burned, do not remove the radiator cap while the engine and radiator are still hot, as fluid and steam can be blown out under pressure.




2. Using a suitable radiator cap tester, pump the tester and measure the relief valve opening pressure.
Standard opening pressure: 74 - 103 kPa (10.7 - 14.9 psi).
Minimum opening pressure: 59 kPa (8.5 psi).

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.
^ Use the tester's maximum reading as the opening pressure.
^ If the opening pressure is less than minimum, replace the radiator cap.




3. Fill the radiator with coolant and attach a suitable pressure tester to the water filler.
4. Warm up the engine.
5. Pump it to 118 kPa (1.2 kg/sq cm, 17.1 psi), and check that the pressure does not drop.
^ If the pressure drops, check the hoses, radiator or water pump for leaks.
^ If no external leaks are found, check the heater core, cylinder block and cylinder head.
6. Reinstall radiator cap.