Component Tests and General Diagnostics

1. Check engine coolant level.

WARNING: NEVER REMOVE THE PRESSURE RELIEF CAP UNDER ANY CONDITIONS WHILE THE ENGINE IS OPERATING. FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN DAMAGE TO THE COOLING SYSTEM OR ENGINE AND/OR PERSONAL INJURY. TO AVOID HAVING SCALDING HOT COOLANT OR STEAM BLOW OUT OF THE COOLING SYSTEM, USE EXTREME CARE WHEN REMOVING THE PRESSURE RELIEF CAP FROM A HOT DEGAS BOTTLE. WAIT UNTIL THE ENGINE HAS COOLED, THEN WRAP A THICK CLOTH AROUND THE PRESSURE RELIEF CAP AND TURN IT SLOWLY ONE TURN (COUNTERCLOCKWISE). STEP BACK WHILE THE PRESSURE IS RELEASED FROM THE COOLING SYSTEM. WHEN CERTAIN ALL THE PRESSURE HAS BEEN RELEASED, REMOVE PRESSURE RELIEF CAP (STILL WITH A CLOTH).

2. Disconnect the electrical connector from the water temperature indicator sender unit.
3. Remove the water temperature indicator sender unit from the engine.

NOTE: With the pressure relief cap installed and the cooling system pressure relieved, only a small amount of coolant will be lost when the water temperature indicator sender unit is removed from the engine.

4. Install the adapter fitting from Radiator/Heater Core Pressure Tester tightly into the intake manifold in place of the water temperature indicator sender unit.
5. Disconnect the radiator overflow hose from the degas bottle.
6. Install a separate hose, making sure hose is firmly installed on the reservoir overflow nipple. Insert the free end of the hose into a container of water.
7. Pressurize the engine cooling system. Observe the gauge reading for approximately 2 minutes. Pressure should stabilize at pressure relief cap rating and should not drop during this time.

CAUTION: If the pressure drops, cheek for leaks at the engine to heater core hoses, engine to radiator hoses, water valve hose (if applicable), water hose connection gasket, radiator, and heater core. Also, refer to diagnosis and testing of the engine if a leak cannot be located in the cooling system. Any leaks that are found must be corrected and the system rechecked.

NOTE: If the pressure relief cap does not hold pressure, remove and wash the pressure relief cap in clean water to dislodge any foreign particles from the gaskets. Check the sealing surface in the degas bottle filler neck. Inspect threads on both the degas bottle filler neck and the pressure relief cap for damage and foreign material. If a leak is detected, check inside the vehicle for possible heater core leaks.

8. Release system pressure by loosening the pressure relief cap and remove the adapter.
9. Install the water temperature indicator sender unit; check coolant level and replenish, if necessary.