Cooling System Pressure Test

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. 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: The engine cooling system is filled with Motorcraft® Orange Antifreeze/Coolant. Mixing coolant types degrades the corrosion protection of the coolant. Do not mix coolant types. Failure to follow these instructions may result in engine or cooling system damage.

NOTE: Always fill the cooling system with the manufacturer's specified coolant. Chemically flush the cooling system if a non-specified coolant has been used. Refer to COOLING SYSTEM FLUSHING . Failure to follow these instructions may damage the engine or cooling system.

NOTE: During normal vehicle operation, Motorcraft® Orange Antifreeze/Coolant may change color from orange to pink or light red. As long as the engine coolant is clear and uncontaminated, this color change does not indicate the engine coolant has degraded nor does it require the engine coolant to be drained, the system to be flushed, or the engine coolant to be replaced.

NOTE: Vehicles have a pressure relief cap on the degas bottle and no radiator cap.

Turn the engine OFF.
Check the engine coolant level. Adjust the coolant level as necessary.
Attach the D-Gas Adapter to the degas bottle nipple and overflow hose. Install the Radiator Tester to the quick connect fitting of the D-Gas Adapter.

Fig 1: Checking Engine Coolant Level
Courtesy of FORD MOTOR CO.
NOTE: Do not pressurize the cooling system beyond the maximum pressure listed in Specifications or cooling system components may be damaged.

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

Slowly press the plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained. If the pressure reading exceeds the maximum cap pressure listed in the specifications table, install a new pressure relief cap.
If the system does not hold pressure, remove the pressure relief cap and wash in clean water to dislodge all the foreign material from the gasket. Check the sealing surface in the filler neck of the degas bottle for nicks or cuts. Install the pressure relief cap.
Pressurize the engine cooling system as described in Step 4. Observe the gauge reading for approximately 2 minutes. Pressure should not drop during this time. If the pressure drops within this time, inspect for leaks and repair as necessary.
If no leaks are found and the pressure drops. the pressure relief cap may be leaking. Install a new pressure relief cap and retest the system.
If no leaks are found after a new pressure relief cap is installed, and the pressure drops, 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.
For 2.0L GTDI , if no leaks are found after a new pressure relief cap is installed and the pressure drops, the leak may be internal to the radiator transmission cooler or the transmission fluid cooler/warmer. Inspect the coolant for transmission fluid and the transmission fluid for coolant. Install a new radiator. Refer to RADIATOR - 2.0L GTDI . Install a new transmission fluid cooler/warmer. Refer to TRANSAXLE/TRANSMISSION COOLING - 6F35 . Repair the transmission as necessary. Refer to AUTOMATIC TRANSAXLE/TRANSMISSION - 6F35 .
Release the system pressure by loosening the pressure relief cap. Check the coolant level and adjust as necessary.