Burning oil smell

[VictorH]

Need a little help tracking down a burning oil smell. I have '09 M3 with 146,000 miles. It's my daily driver and has been great. Under normal driving no smell or odor whatsoever.

The first couple times I noticed this (started about 2 weeks ago) I always thought it was the car in front of me, but now I know for sure it's me! Anyway, I only get the oil burning smell if I'm above 5,000 rpm and full throttle which I don't do very often on the street. The oil smell comes into the cabin and lasts maybe 30 seconds or so, then it's gone. I've looked on both sides of the engine (airbox out) and don't see anything that looks like it's leaking. Headers don't have any stains, but it's also hard to see them completely.

I have track event next weekend and was hoping maybe to track this down before I'm blowing out oil from somewhere. No change in oil level so whatever it is, it's really a small amount.

Anyone run into this and what might your suggestions be? Thank you.

[pbonsalb]

Probably leaking valve cover gasket. Obviously it’s not a bad leak.

[drrust]

Once when I was installing the plenum, one of the oil separators broke on a seam. I would check to make sure those pieces are still intact.

[VictorH]

Okay, it's now a few months later, now at 151,000 miles. Valve covers replaced with reconditioned units, new OEM gaskets, bolts grommets, spark plug tube as well as new oil separaters on both sides.

I still have the exact same oil burning smell. Visually and by touch (where I can't see) I don't find any oil leaks. I don't see any oil stains on the headers, at least where I can see.

The circumstances:
1) Initial "hard" acceleration, 50% or more throttle, 4,000+ rpm, get an almost immediate oil smell in the cabin, lasts 30 seconds or so, then resolves. Windows closed so it's coming through the vents.
2) If I do this a few times in a row the smell will not recur as strongly or at all, it's just the initial, higher rpm, higher throttle input.
3) No smoke out the tail pipe I can see, my car does not burn oil between oil changes, the oil level is constant so whatever the amount it's pretty small.

Any other ideas as to the source or what to check?

[randrews15]

Have you checked the oil filter housing gasket? That can leak and initially hard to tell my X5 started to leak out of there for a while and didn't catch it till the side of the block was coated in oil. Obviously, it's a small leak that sounds like it becomes more evident as you increase crank case pressure.

[jvictormp]

Are you sure it didn't happen since you own the car?

Because I smell that since I own mine. Every full throttle high rpm, the smell comes. I find it satisfying actually it's the beast's smell, smells like power.

I think it comes from the exhaust tip, due to the vortex generated in the rear of the car, coming into cabin by any hole.

[mapster37]

i would check oil filter housing gasket and oil pan gasket next

[VictorH]

All good ideas. The smell is new and I've owned the car since new.
Oil pan gasket was replaced at 90,000 miles with rod bearings and I've had the aluminum lower engine plate off in the last 8 weeks (when I dropped a bolt doing the valve cover gaskets).

The oil filter housing is a good idea. Where is the gasket for the housing? That will be the next thing I check. My motor in general has been pretty clean so if I see something it should be obvious. Thanks for the tips.

[jvictormp]

Originally Posted by VictorH

All good ideas. The smell is new and I've owned the car since new.
Oil pan gasket was replaced at 90,000 miles with rod bearings and I've had the aluminum lower engine plate off in the last 8 weeks (when I dropped a bolt doing the valve cover gaskets).

The oil filter housing is a good idea. Where is the gasket for the housing? That will be the next thing I check. My motor in general has been pretty clean so if I see something it should be obvious. Thanks for the tips.

Oil filter housing gasket is an o'ring around the thread.

You'll need a 36mm socket or box wrench to remove the housing.

[drrust]

Originally Posted by VictorH

All good ideas. The smell is new and I've owned the car since new.
Oil pan gasket was replaced at 90,000 miles with rod bearings and I've had the aluminum lower engine plate off in the last 8 weeks (when I dropped a bolt doing the valve cover gaskets).

The oil filter housing is a good idea. Where is the gasket for the housing? That will be the next thing I check. My motor in general has been pretty clean so if I see something it should be obvious. Thanks for the tips.

It's at the front. Mine had leaked but one could see oil from underneath at the front of the aluminum belly pan. If you smell it any area near the exhaust would be suspect.

[mapster37]

oil filter housing gasket, not the filter o-ring.

[jvictormp]

Originally Posted by mapster37

oil filter housing gasket, not the filter o-ring.

Sorry, misunderstood it.

[widetyres]

Originally Posted by VictorH

All good ideas. The smell is new and I've owned the car since new.
Oil pan gasket was replaced at 90,000 miles with rod bearings and I've had the aluminum lower engine plate off in the last 8 weeks (when I dropped a bolt doing the valve cover gaskets).

The oil filter housing is a good idea. Where is the gasket for the housing? That will be the next thing I check. My motor in general has been pretty clean so if I see something it should be obvious. Thanks for the tips.

Big time thread resurrection, but VictorH did you find out what was causing your oil vapour leak/burning smell in the end? I have the same issue and really struggling to find it. I can't see any leaks at the top of the engine, and nothing near the exhausts.

Did you replace the oil filter housing gasket? Did it help?

I switched to an ester based oil and the stuff is toxic - I keep coughing loads after being in the car after a "spirited" drive - I defo need to get it sorted.

Cheers.