Dipstick dislodged and resultant oil spray OM606
 

Three or four times now I've found my dipstick dislodged and resultant oil spray on my 97 E300. Enough oil to cause the low oil message on the dashboard once (I refilled...and then subsequently changed the oil).

It's not everyday, and I'm trying to find a pattern. The first couple times the weather was cold (5-15F) and I had done an italian tuneup on highway onramps a couple times. Today it's in the teens, and I was driving through town with no load on the engine. The telltale sign is that I can smell oil in the cabin when I'm at a stop.

The dipstick o-ring is probably getting tired and doesn't make a real tight fit when in place, but it's not loose enough to have play in it. I tried to put in a fresh O-ring, but don't have an exact match, and the closest one is too big to fit the dipstick back in the tube.

My first fear was excessive blowby, but it doesn't happen all the time. Many cold days it's been fine, and many hard accelerations it's been fine.

Is there some EGR or PCV related valve that may be sticking, thus allowing excessive crankcase pressure?

I searched the forum, but didn't find any issues similar to this.

Any guidance is appreciated. 195k on the clock.

There have been a few threads on this topic in regard to 617's. I think at least once the situation has been resolved with a new o-ring.

I would guess that it might be a plugged PCV system. The ones on the NA cars are quite a bit more complex and subject to damage and blockage. More so than the turbo version.

I'm having trouble finding a good schematic of the crankcase ventilation system. My Star CD seems woefully inadequate, and the Russian diagram site didn't seem to have much either.

Anybody have a source for a NA OM606 PCV system diagram?

Thanks

Mark

trust me over time dipstick oil ring goes bad.