Leaks in the cooling system and the operation of the safety valve in the cover can be checked using the VW 1274.
Install the device on the filler hole in the expansion tank. Pressurize the system to 1.0 bar using the hand pump of the control device. If the pressure drops, find the leak and fix it.
To check the safety valve in the cap of the expansion tank, install the device on the cap. Create pressure in the system. At a pressure of 1.2-1.5 bar the valve should open.
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