Dipstick popping out - PeachParts Mercedes-Benz Forum

sf veggiebenz I · #1 10-24-2009, 12:10 AM

I've had a problem for a couple of weeks now, the dipstick pops out when I floor it and engine revs above 4 - right when the turbo kicks in. Oil would be splattered all over the engine, blow-by smoke from the rear and smoke in the engine. Once it spit up oil into the air filter and really dirtied up the MAF and triggered a CEL. Luckily MAF cleaner and a new filter cleared things up, but the dipstick is still popping out. The car runs fine as long as I don't gun it and keep it under 4,000 rpm.
Any ideas on possible solutions?

Thanks
Mitchell

#2 10-24-2009, 12:14 AM

What model/year are we talking about?

compu_85 · #3 10-24-2009, 12:27 AM

Sounds like the rings are very, very tired and when the boost comes up the blowby overcomes what the stock crank case vent can handle and finds the next easiest path out!

The stock crank case vent isn't plugged, is it?

-Jason

sf veggiebenz I · #4 10-24-2009, 01:17 AM

Sorry I forgot to mention that it is a 99 e300.

pawoSD · #5 10-24-2009, 01:31 AM

Check the vent from the valve cover to make sure it is not clogged....it likely is if that is happening.

I would think that if the rings are worn enough for that to be the cause, the engine would probably have a real hard time starting, or would not start at all...from low compression.

#6 10-24-2009, 01:32 AM

I would have a compression test done. If you have significant blow-by, it may be enough to pressurize the crankcase and push oil out the dipstick.

#7 10-24-2009, 01:36 AM

Quote:

Originally Posted by pawoSD

Check the vent from the valve cover to make sure it is not clogged....it likely is if that is happening.

I would think that if the rings are worn enough for that to be the cause, the engine would probably have a real hard time starting, or would not start at all...from low compression.

Hopefully, it is just a clogged vent. However, I had a ton of blow-by in a 617 engine due to a loss of compression in only one cylinder. The car started and ran reasonably well, but one cylinder was down to <200 psi and it was blowing oil everyplace at highway speeds.

JEBalles · #8 10-24-2009, 09:47 AM

x2 check compression and pcv. doesn't sound good though.

sf veggiebenz I · #9 10-24-2009, 12:46 PM

I'm pretty handy and have changed the glowplugs and rebuilt injectors, so I just need a little guidance to where and what I'm checking. On an e300 is it pcv pipe that goes into the MAF and then the airfilter? Or is there another connection I should be checking?

Thanks
Mitchell

79Mercy · #10 10-24-2009, 09:45 PM

Yes thats the correct hose.

May i ask if you are running it on veggy oil?

sf veggiebenz I · #11 10-24-2009, 11:20 PM

I took apart the pieces that connect the air filter to the turbo and the tube going into the engine and no blockage there. Following the tube toward the back of the engine with no resistance until right at the end of engine block. Hard to blow air into it. Did poke a nylon string into the hole to see if there was any blockage but didn't seem to be any.

To answer the above question, I have been running on veggie oil for the past year - Greasecar. I purge at the end of the day with biodiesel. I've experimented with the car running on veggie oil and biodiesel and revved it to 4000 and oil splattered all over under both conditions.

Like I said earlier, starts up fine, runs great but if I gun it I get a big mess in the engine. I've ordered an oring from the dealer, I just might try one from the hardware store but don't want to experiment again b/c a quart of oil sprays all over the place.

pawoSD · #12 10-24-2009, 11:43 PM

I don't find it all that surprising to see issues like this happening with engines running on veg oil. There's really no telling what it might do to a given engine. It might have coked the rings, causing excessive blowby....thus the excessive crankcase pressure.