Checking the valve (VW Golf 4)

Execution order

1. Unscrew the cap from the valve.

2. Apply a little saliva to the valve. When a bubble forms, screw the valve back on with the cap.

Warning: Use only the metal cap to tighten the valve.

3. Recheck the valve. If bubbles continue to form and the valve cannot be tightened further, replace it.

4. Be sure to screw the cap on.