Checking the radiator cap and radiator

The cooling system is under pressure. The expansion tank cap opens when the pressure rises to a certain value (designation «140» means 140 kPa).

To test the cap, you will need a pump that is used to test the radiator. Install the pump on the plug, turn it on and let it run until the valve opens. A used cap will open at a lower pressure than a new one.

With this pump, you can check the cooling system for leaks in the same way. Install the pump on the expansion tank. Bring the pressure up to 100 kPa and make sure that the pressure gauge can withstand this pressure for at least 5 minutes.