Wagoneer L6-258 4.2L VIN C 2-bbl (1982)
Thermal Vacuum Valve: Testing and Inspection
EGR CTO
NOTE: Engine coolant temperature should be below 100° F.
1. Check vacuum lines for leaks and correct routing.
2. Disconnect vacuum line at EGR valve and connect a vacuum gauge.
3. Operate engine at approximately 1,500 rpm. No vacuum should be indicated on gauge.
NOTE: If vacuum is indicated, replace EGR CTO switch.
4. Idle engine until coolant temperature exceeds 100° F on four cylinder engines, 115° F (black color coded) or 160° F (yellow color coded).
5. Operate engine at 1,500 rpm, ported carburetor vacuum should be indicated on gauge.
NOTE: If vacuum is not indicated, replace EGR CTO switch.
