smoke coming from under air cleaner - PeachParts Mercedes-Benz Forum

NH82W123 · #1 10-13-2014, 09:20 PM

I have a noticeable amount of smoke coming from somewhere under the air cleaner (or so it looks) of my 82 300D. It's not exactly billowing, but I can see it coming from around the hood when idling at a stop. And there is a noticeable smell in the cabin - more like burning engine oil than exhaust I think. Is it OK to remove the air cleaner and run the engine in an attempt to see where the leak is coming from? Any special precautions I should take before doing it?

Thanks.

Charlie

uberwasser · #2 10-13-2014, 10:04 PM

You can do that for a little while. Hopefully just a valve cover leak on to your exhaust manifold.

dieselbenz1 · #3 10-13-2014, 11:32 PM

I experienced loss of power in my 123 on the highway and once fully stopped there was a full blown fire under the hood. Turned out the wast gate was gummed in the fully open position but after a good cleaning everything went back to normal. When you say idle do you mean both with your engine cold and hot?

unkl300d · #4 10-14-2014, 12:43 AM

Probably just a return hose loose.

Look under with a flashlight or remove the cover...

good luck !

vstech · #5 10-14-2014, 08:02 AM

there is a 15mm aluminum tube that goes from the catch can to the upper oil pan. it's held in place with a bolt to the exhaust manifold. they often get dinged up, and rattle loose. pull the air cleaner, and change the o-ring on the bottom, then pull the tube, and change the o-ring on the oil pan, then remount the air cleaner, and reseat the tube on both ends. the o-rings will hold the tube in place, then strap the tube solid.

NH82W123 · #6 10-14-2014, 01:15 PM

Thanks for the replies.

Quote:

Originally Posted by dieselbenz1

When you say idle do you mean both with your engine cold and hot?

I started the car this morning after an overnight sit and I saw some smoke - not as much as when the engine is hot, but it was definitely there and coming from the same area.

Quote:

Originally Posted by unkl300d

Probably just a return hose loose.

What kind of return hose do you mean? I'm guessing not fuel injector return, but I checked those anyway and they're in good shape.

John - you might be on to something with the catch can-to-oil pan line. The air cleaner bracket broke recently so I'm sure it was thrashing around for a bit. I'll pull the air cleaner off this weekend and take a closer look...

unkl300d · #7 10-14-2014, 02:15 PM

Sorry for my lack of specificity, its no better today. Like a 'breather' hose. Might be what VSTech was referring to. In any event, once you remove the air cleaner housing, you will probably discover the loose or poorly fitted hose/pipe...

FryBird · #8 10-16-2014, 01:40 AM

+1 What vstech said, I had same problem, my o-ring was gone on the filter housing connection ( on the bottom) that goes to the oil pan

ROLLGUY · #9 10-16-2014, 02:23 AM

Quote:

Originally Posted by FryBird

+1 What vstech said, I had same problem, my o-ring was gone on the filter housing connection ( on the bottom) that goes to the oil pan

+2. My bet is exactly that.

BillGrissom · #10 10-16-2014, 04:05 PM

With air filter on, feel underneath to see if the metal drain tube is seated securely on the "oil catcher" drain stub. Indeed, always do so after re-installing the air filter. Remove the air filter to see it, and replace the O-ring if you do so. It snakes underneath the turbo, ending on a stub on the "upper oil pan", just behind the larger turbo oil drain tube. It has a retainer that bolts to the lower "turbo support bracket", which keeps it from popping out of place, but that retainer usually breaks from engine vibration.