Thermal Vacuum Valve: Testing and Inspection

A .020 inch (.5 mm) 3 ohm resistance wire is integral with thermo valve lead wire.
1. Disconnect vacuum hose from thermo valve T-fitting.
2. Using mouth, blow air into disconnected thermo valve vacuum hose.
3. Thermo valve should be closed when engine is warm, and opened when ambient temperature is below 68° F.
4. If valve does not perform as outlined above, replace it.