D150 1/2 Ton Pickup 2WD V6-239 3.9L VIN X FI (1988)
Positive Crankcase Ventilation: Testing and Inspection
PCV Valve Vacuum Check
PCV VALVE TEST
1.
With engine idling, remove PCV valve from rocker cover. If valve is not plugged, a hissing sound will be heard as air passes through the
valve, and a strong vacuum should be felt when a finger is placed over the inlet of the valve.
Crankcase Inlet Vacuum Check
2.
Reinstall the PCV valve, then remove crankcase inlet air cleaner. With engine idling, loosely hold a piece of stiff paper (such as a parts tag)
over the opening in the rocker arm cover. After allowing about a minute for the crankcase pressure to reduce, the paper should be drawn
against the opening in the rocker arm cover.
