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Discussion Starter · #1 ·
I have an X3 E83 M54. A few months back, I realized that there was smoke coming out from the vent and I thought it was just an one time event because it did not happen for a few days. The second time it happened, I tried to figure out where the smoke was coming from and it seems that its coming from somewhere near the end of the exhaust manifold. After a while, I realized that smoke comes out only when it is parked for more than 24 hrs. and it gets worse if it stays for a few days. My conclusion now it is that some liquid builds up somewhere near the exhaust manifold and smoke comes out when it burns the liquid. I said some liquid, because I asked a friend if it could be an oil leak, but he said that the smell is not like oil burning, but some other liquid?? I checked the plastic cover under the engine bay and did not see any sign of an oil or any liquid leak, which is very confusing since it is clear that something is building up and burning when the engine gets hot. Any ideas anyone?
By the way, I usually use the vent circulating only inside the car to avoid the smoke and if I drive for more than 30 mins, the smoke is gone and I can open the vent with fresh air and don't smell the smoke at all.
 

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Probably is a leaking valve cover?

Have you pulled the ignition coils and checked for oil in the wells?
 

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I have an X3 E83 M54. A few months back, I realized that there was smoke coming out from the vent and I thought it was just an one time event because it did not happen for a few days. The second time it happened, I tried to figure out where the smoke was coming from and it seems that its coming from somewhere near the end of the exhaust manifold. After a while, I realized that smoke comes out only when it is parked for more than 24 hrs. and it gets worse if it stays for a few days. My conclusion now it is that some liquid builds up somewhere near the exhaust manifold and smoke comes out when it burns the liquid. I said some liquid, because I asked a friend if it could be an oil leak, but he said that the smell is not like oil burning, but some other liquid?? I checked the plastic cover under the engine bay and did not see any sign of an oil or any liquid leak, which is very confusing since it is clear that something is building up and burning when the engine gets hot. Any ideas anyone?
By the way, I usually use the vent circulating only inside the car to avoid the smoke and if I drive for more than 30 mins, the smoke is gone and I can open the vent with fresh air and don't smell the smoke at all.
Oil huid seals leaking
 

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To the OP, not to the guy who doesn’t understand forums: replace your rocker cover gasket. Your exhaust manifolds are burning away leaked oil when the engine cools, parts shrink and oil leaks.


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To make sure, run your fingers (maybe in a rubber glove) along the seam of plastic valve cover and cylinder head above the exhaust manifold - engine cold. If you come up with oil you have found your source.

Oil burning has a very distinctive smell...different from coolant..do you smell oil burning?

Honestly, you probably need a new valve (rocker) cover gasketwith grommets AND a new CCV. If your CCV is original, definitely replace it. A failed CCV can add pressure to the crankcase and force oil out onto the exhaust manifold.

Overfilling the engine with oil can do the same thing
 

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Add to that, different oils smell different when burned. I’ve had power steering fluid weeps burn off the engine, but that would be port side not starboard.

If the head has ANY oil film on it where the rocker cover sits, you have an oil leak from that gasket, which is also a vacuum leak. If you run your fuel trims you’ll likely see them 7-10% positive as a result.


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Discussion Starter · #10 ·
Thank you everyone for all the comments!
I did some checking suggested in a few websites with photos and I found the exact place where the oil is dripping into the exhaust manifold. Also, I took out the plastic cover and also found some oil residues dripping from the valve cover, so I have to replace the gasket there for sure. @dukedkt442 I think you are right, different oils smell different.
 

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If not done already, consider changing the two upstream O2 ("Lamda") sensors too while in there.
 

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If everything on these things were so easy (but not cheap ...) to diagnose and fix! :)
 
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