W250 3/4 Ton Pickup 4WD V8-318 5.2L VIN Y FI (1988)
PCV Valve Test
3.
With engine off, remove PCV valve from rocker cover and shake the valve. A rattling noise should be heard, indicating that the valve is free.
4.
If the system passes the above tests, no further service is required. If not, replace the PCV valve and recheck the system. Do not attempt to
clean the PCV valve.
5.
With a new PCV valve installed, if the paper is not drawn against the crankcase inlet air cleaner opening with considerable force, it will be
necessary to clean the passage in the throttle body. Also, the PCV hose will have to be cleaned or replaced.
