Component Tests and General Diagnostics

WARNING: Never remove the radiator cap under any conditions while the engine is operating or when the cooling system is hot. Failure to follow these instructions could result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the radiator, use extreme care when removing the radiator cap. Wait until the engine has cooled, then wrap a thick cloth around the mediator cap and turn it slowly to the first stop, step back while the pressure is released from the cooling system. When the pressure has been released, press down on the radiator cap (still with a cloth), turn and remove it.

1. Shut off the engine.
2. Open the hood and install protective fender covers.
3. Carefully remove the pressure relief cap from the radiator coolant recovery reservoir to relieve pressure in cooling system. Add coolant to radiator coolant recovery reservoir as necessary.
4. Install the adapter fitting from Pressure Tester tightly between overflow/air purge nipple and overflow/air purge hose at the radiator coolant recovery reservoir. Reinstall the pressure relief cap.
5. Attach the pressure pump and gauge to the adapter fitting and pressurize the cooling system to the pressure relief cap lower limit.
6. Pressurize the cooling system. Observe the gauge reading for approximately two minutes. Pressure should not drop during this time.
- If system holds pressure, proceed to Step 8.
- If the pressure drops, check for leaks at the engine to heater core hoses, engine to radiator hoses, bypass hose, water valve hose (if applicable), thermostat housing gasket, radiator and heater core, etc. Also refer to engine system checks if a leak cannot be located in the cooling system. Correct any leaks found and recheck the system.
7. Release the system pressure by loosening the pressure relief cap. Check the coolant level. Replenish as necessary with the correct coolant solution.
8. Check the radiator overflow hose for any obstructions which may block the flow of coolant either to or from the radiator coolant recovery reservoir.
9. Conduct the Pressure Relief Cap Pressure Test.