Cooling System Pressure Test

Cooling System Pressure Test

WARNING: Never, under any circumstances, remove the coolant expansion tank pressure cap while the engine is operating. To avoid having scalding hot water or steam blow out of the cooling system, use extreme care when removing the coolant expansion tank pressure cap from a hot cooling system. Wait until the engine has cooled, then wrap a thick cloth around the coolant expansion tank pressure cap and turn it slowly until the pressure begins to release, step back while the pressure is released from the system. When certain all the pressure has been released (still with a cloth) turn and remove the coolant expansion tank pressure cap. Failure to follow these instructions may result in damage to the cooling system, engine and/or cause personal injury.

1. Switch the engine off.
2. Open the hood and install protective fender covers.
3. Carefully remove the coolant expansion tank pressure cap from the coolant expansion tank to relieve pressure in the cooling system. Add coolant to coolant expansion tank as necessary.
4. Install the pressure tester equipment to the cooling system following manufacturers instructions. Reinstall the coolant expansion tank pressure cap (if pressure test equipment is not installed to the coolant expansion tank).
5. Pressurize the cooling system to the coolant expansion tank pressure cap lower limit.
6. Observe the gauge reading for approximately two minutes. Pressure should not drop during this time.
^ If system holds pressure, continue from step 8.

If system holds pressure, continue from step 8.
^ If the pressure drops, check the complete cooling system for leaks. Also refer to engine system checks if a leak cannot be located in the cooling system. Correct any leaks found and recheck the system.

If the pressure drops, check the complete cooling system for leaks. 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 and remove the pressure test equipment. 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 coolant expansion tank.
9. Conduct the coolant expansion tank pressure cap pressure test.