Wagoneer L6-258 4.2L VIN C 2-bbl (1982)
Thermal Vacuum Valve: Testing and Inspection
Thermal Vacuum Switch
1. Cool air cleaner to a temperature below 40° to 50° F.
2. Disconnect vacuum hoses from Thermal Vacuum Switch (TVS), then connect an external vacuum source to one nipple and a suitable vacuum
gauge to other nipple.
3. Apply vacuum to TVS and observe gauge.
4. If gauge indicates vacuum through TVS when temperature is below 40° to 50° F, replace TVS.
5. Start and run engine until air cleaner temperature is above 50° F. If gauge does not indicate vacuum, replace TVS.
