Oil in air filter


New member
Checked my air filter yesterday and it had oil in it. Also the tube from the filter housing to the throttle plate had oil in it. No oil in throttle bore. There is a vent hose from the passenger valve cover to a plastic plenum that is part of the air filter assy. I have a 6.2 with 93,000mi. I am a former mechanic. The truck is maintained.


what year truck ?
is the intake completely stock ?
K&N air filter with to much oil? NO because oil would be present in throttle body
PCV working incorrectly?
it don't sound right, is the vent hose before the air filter that is the only way oil would get on the filter



Air intake system is stock except for K&N air filter. ( not over oiled). Passenger side valve cover has vent into air filter plenum after air filter. I am not using any oil. Do I need a catch can? If so which side, PCV or pass. breather hose? My truck does not have cyl. cancel and is port injected not direct.