Checking the pressure in the engine cooling system

The tightness of the cooling system and the operation of the overpressure valve in the radiator cap can be checked with the VW 1274 and 1274/1 A tester.

Examination

1. Install a control device on the coolant fill pipe of the expansion tank.

2. Using the hand pump of the device, create and maintain an overpressure of about 1.0 bar.

3. If the pressure drops, check the tightness of the cooling system by visual inspection and repair the leaks.

4. To check the overpressure valve in the cap of the expansion tank, install a tester on the cap.

5. Create excess pressure with a hand pump. At an overpressure of 1.2–1.5 bar, the overpressure valve should open.