F 250 4WD Pickup L6-300 4.9L (1982)
Thermal Vacuum Valve: Testing and Inspection
Thermactor PVS (With 2 Connectors)
PROCEDURE
1. Disconnect both vacuum hoses at PVS valve. Connect vacuum gauge to bottom connector on PVS.
2. Using an external vacuum source, apply at least 10 inches Hg vacuum to top connector. With engine cold, there should be no vacuum reading. If
there is, replace PVS.
3. Start engine and allow to reach normal operating temperature. With 10 inches Hg vacuum applied, there should be a vacuum reading. If not, PVS
is defective and should be replaced.
