F 250 4WD Pickup L6-300 4.9L (1982)
Thermal Vacuum Valve: Testing and Inspection
Electric PVS High Temp Coolant Lock Out Vacuum
1975-82 Vehicles With Catalytic Converter
1. Disconnect vacuum line from air bypass valve to PVS valve at air bypass valve and connect to vacuum gauge.
2. With transmission in Park or Neutral and parking brake applied, start engine and allow to idle.
3. With engine at normal operating temperature, there should be a vacuum reading. If not, PVS is defective and should be replaced.
