oil out the tailpipe - OM616 - PeachParts Mercedes-Benz Forum

herring · #1 05-07-2008, 12:43 PM

Shortly after buying my car, I noticed that it left a bit of dark smudge on the asphalt where I let it warm up (it was winter, so there was a some effort in starting and a fair bit of warming up done).

I figured that the smudge was soot, what with all the smoke of cold-weather starting. I recently figured out that the car is actually putting a fine mist of oil out the exhaust pipe.
Oil consumption is pretty low, so we're not talking about a huge bunch of oil here...maybe a quart in a few thousand miles. It's hard to tell because I had some engine seals replaced in February, and only bought it in January.
With the warmer weather, there is some gray smoke at startup, and under heavy acceleration. Otherwise only little puffs of gray smoke here and there. Never had any black smoke at any time.

The engine does have about 309,000 miles, never been overhauled. But I did the blowby oilcap test when I bought it (and again over the weekend) and it doesn't even rattle--just tips a bit to the side and lets a flow of air out. Think nice breeze, not Hurricane Katrina.

I have gotten the engine started in the 20s with no help from the block heater, so I figure the compression can't be too horrible.

I guess what I'm asking is, is this normal for an engine of my mileage, and it will continue doing this peacefully until I get it rebored? Or is it something of more serious concern? How much would one expect to pay to have an OM616 engine given its "300,000 mile service"?

rrgrassi · #2 05-07-2008, 12:48 PM

Diesel is a lightweight oil. Lots of cars also get the sooty bumper, which is like a fine oil mist when touched. Our 2006 VW TDI gets the sooty bumper, but strangely my MB does not.

t walgamuth · #3 05-07-2008, 01:04 PM

I'd say thats pretty normal. Since the exhaust points down it can be observed on the pavement if it concrete.

Tom W

herring · #4 05-07-2008, 01:28 PM

Quote:

Originally Posted by t walgamuth

I'd say thats pretty normal. Since the exhaust points down it can be observed on the pavement if it concrete.

Tom W

I'm noticing it on recent (i.e. dark) black asphalt, though. Diesel motor oil sure gets black. I changed mine last weekend at a relative's, drove home and went to check the oil level again (just to be sure)--black.
The staining is why I thought there might be a problem. I live in a condo complex and between the drips of oil from the engine (not too bad, but they add up), the exhaust, and a past fuel leak, I feel like I'm making a mess of my parking space.

What about if I clipped off the end of the tailpipe and JBWelded on a piece pointing out to the side?

nhdoc · #5 05-07-2008, 01:30 PM

Assuming your fuel economy is OK I would just ignore it. If you are only consuming oil at the rate you say I don't think it is motor oil. I would bet it is condensing water with soot suspended in it which resembles an oily mix. It will probably only happen in the cold if that is the case.

kerry · #6 05-07-2008, 01:50 PM

Unless you have a reason for thinking it is motor oil, I'd say it's just typical diesel oily soot.
If you're still worried, get two sheets of clean white paper. Put one under your exhaust for 3 minutes and another under another 616 exhaust for 3 minutes. Photograph the results and post them here.

herring · #7 05-07-2008, 02:23 PM

Quote:

Originally Posted by nhdoc

Assuming your fuel economy is OK I would just ignore it. If you are only consuming oil at the rate you say I don't think it is motor oil. I would bet it is condensing water with soot suspended in it which resembles an oily mix. It will probably only happen in the cold if that is the case.

Well, it's definitely happening in warm weather. I'm not 100% certain about the oil consumption rate because of the work that was done. It may be higher, but I mean it's not guzzling oil at any prodigious rate.

The fact that my odo isn't running right now doesn't help with trying to figure fuel consumption, either.

What does it mean if it IS spitting oil out the tailpipe--say the amount increases over time, what am I in for?

kerry · #8 05-07-2008, 02:26 PM

I don't see how it is possible to ever spew oil out the tailpipe without a turbo.

herring · #9 05-07-2008, 03:04 PM

Quote:

Originally Posted by kerry

I don't see how it is possible to ever spew oil out the tailpipe without a turbo.

Ok, I am going to drive home, (so any water should be burned out of the muffler) then hold a paper towel on the ground underneath the tailpipe for a few minutes and see what I get. I should be able to tell the difference between fresh oil and oily soot carried by water.

bgkast · #10 05-07-2008, 03:06 PM

The other oil out the tail pipe thread with a 603 seems to be caused from really bad valve seals or something allowing oil out the exhaust port.

rrgrassi · #11 05-07-2008, 04:26 PM

And, that oil will not be fresh and clean either.

herring · #12 05-07-2008, 07:52 PM

Ok, got home and ran my finger around the inside of the tailpipe (saved myself a paper towel!) and there was nothing but dry soot. So, your answers must have been right: after starting, water blown out the tailpipe is carrying some soot with it and speckling the ground, which then stays until a good rain.

Whew! Thanks, guys!