Thermal 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.