I thought there was supposed to be a check valve where the oil separator line feeds into the upper oil pan (internally). However, when I questioned Whunter about this, while he had the line out to replace the grommet and o-rings, he stated that there was not a check valve in the lower line. Is this check valve in the upper oil pan maybe? I don't know.

I do know that when I ran a length of wire into the separator drain and then some motor flush at the next oil change, it seemed to cut down on the oil in the air filter area.

Maybe someone here who has had this apart can solve the mystery.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )