Golf GTI L4-1984cc 2.0L DOHC (9A) (1990)
Thermo-Vacuum Valve: Testing and Inspection
1.
Remove the thermo-vacuum valve from the engine, and use a water bath to warm or cool the valve to the proper testing temperature.
2.
Attach a piece of vacuum hose to the valve and blow air through it.
Below 27°C (81°F), the valve should be closed.
Above 49°C (120°F), the valve should be open.
3.
Replace valve if it is not within specification.