Coolant System Pressure Test - Coolant Expansion Tank Systems: Notes

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Always allow the engine to cool before opening the cooling system. Do not unscrew the coolant pressure relief cap when the engine is operating or the cooling system is hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly. Failure to follow these instructions may result in serious personal injury.

NOTE: Vehicles equipped with a coolant expansion tank have the pressure relief cap on the radiator. The pressure relief cap is tested separately.

Turn the engine off.
Remove the pressure relief cap. Fill the radiator with coolant if needed.

Fig 1: Checking Coolant System Pressure Using Gauge
Courtesy of FORD MOTOR CO.
Fit the Radiator Tester to the radiator fill neck.
NOTE: Do not pressurize the cooling system beyond the maximum pressure listed in the SPECIFICATIONS or cooling system components can be damaged.

NOTE: If the plunger of the pressure tester is pressed too fast, an erroneous pressure reading results.

Slowly press the plunger of the pressure test pump to the maximum allowed pressure and hold for 2 minutes. If the pressure drops within this time, inspect for leaks and repair as necessary.
If no leaks are found and the pressure drops, the leak may be internal to the radiator transmission cooler. Inspect the coolant for transmission fluid and the transmission fluid for coolant. Repair as necessary.
If there is no contamination of the coolant or transmission fluid, the leak may be internal to the engine. Inspect the coolant for engine oil and the engine oil for coolant. Refer to ENGINE SYSTEM - GENERAL INFORMATION to diagnose the engine.