Instead of the radiator cap, screw in the device adapter.
Caution: Cover the radiator nipple with a rag for safety reasons. Remove the radiator cap only when the radiator has cooled to at least body temperature. Sometimes hot water splashes can cause burns.
Increase the pressure in the cooling system with a pump. The pressure should be 1.8 bar.
The pressure should not drop within 2 minutes. If the pressure drops, find the leaks.
Release the pressure and slowly roll up the adapter.
Check the relief valve. It is located in the radiator cap. Its job is to open the system and drain the coolant into the expansion tank.
To check the safety valve, screw the filler cap onto the appliance as shown in Fig. G-1808.
Create pressure. In the pressure range of 0.7-1.0 bar, the valve should open. Otherwise, replace the cover.
Screw the cap onto the radiator neck.
If the rubber gasket is damaged, replace it.