Rollover Check Valve

Remove rollover check valve from vehicle. Blow into port "A". Air should flow out of port "B". Cover port "B". Blow into port "A". Air should flow through port "C". See Fig 1 . If not, replace valve.

Fig 1: Testing Rollover Check Valve

Courtesy of FORD MOTOR CO.

Fig 2: Fuel Evaporation System

Courtesy of FORD MOTOR CO.