996 carrera

[artkathe]

Has anyone run across excessive crankcase vacuum in a 3.4L ? there is a real bad whistling noise caused by air being pulled past the what sounds like the rear main seal. if you pull the dip stick the noise goes away. you can hardly remove the oil filler cap with the engine running. ive seen plenty of oil seperators go bad causing all sorts of problems but never this one ant ideas?

[phillipj]

Sounds like AOS to me. Does your car have the other AOS symptoms as well? (smoke, rough idle etc?) There is another AOS thread here from this week where RFM provided a test for the AOS. Try to search for it..

[artkathe]

Sounds like AOS to me. Does your car have the other AOS symptoms as well? (smoke, rough idle etc?) There is another AOS thread here from this week where RFM provided a test for the AOS. Try to search for it..

It does smoke on r/hand corners ,seemed like oil being thrown onto header from leaking spark plug tubes but could be from the AOS.

Thanks for your insite

[phillipj]

If it were your spark plug tubes oil would get on to the headers even in a straight line. They usually leak under heavy acceleration.

From all the faulty AOS posts I have read here yours sounds like a classic case. As long as the smoke is heavy and white (not blue or black :o .)