[s2kman]

Hi e90post,

Hopefully some of you can share if you had similar issues.
Car is '07 335i with ~78K miles on it.

The other day in aug-sept. I noticed smoke coming from the engine bay. Stopped the car, looked under the hood... nothing in there, a little smell of burned oil. Started the car, checked the oil level - everything is Ok. So it was like that for couple of weeks (oil was on Ok level, never had to add oil) before I got car for check at one of the NJ shops.
Guys checked the car and said that it was a head gasket leak. So they changed it, and it looked like smoke disappeared.

Now after ~1000K miles it's back again. I can see the drip marks on cat converter and looks like it is coming from exactly the same place as before.

Please advice... I don't think it is a head gasket, since it was changed 1K miles ago. It leaks somewhere around the back turbo housing as far as I can see. Is there some oil feeds around that tend to leak? I'm not actually sure if it's oil, but not sure if coolant lines go around there too.

I just don't want to end up changing another gasket because I don't think it's that.

Let me know what do you think...

[JamesM3M5]

You sure they didn't just replace the valve cover gasket, not the head gasket? Also, they can get kinked or fold under and not seal properly. You'll need to remove the cowl and use an inspection mirror to see the gasket all the way around. Otherwise it could be a leaky o-ring feeding the turbo.

[s2kman]

pretty sure about the head gasket since I inspected after them, some places that you can't easily reach by hand were cleaned pretty well around the the spot between head an block

[JamesM3M5]

Head gasket job is about 27.5 hours of work per the BMW KSD. That's removal of the head. Plus over $800 in parts. You sure it was the head gasket?

Regardless, take it back to the shop to ensure they didn't mess up the valve cover gasket replacement.

[Syndicategt]

Had the same issue. I thought for the longest time my turbo seals were leaking oil but replaced my valve cover gasket and oil lines going to the turbos, the problem stopped. Not sure which of the 2 it was since was done at roughly the same time. If your headgasket is leaking, you would notice oil in your coolant, which would look frothy.

[s2kman]

Will bring it to the shop again this weekend. Probably will not have time to inspect it myself during the week, but thanks for the heads up... will look into turbos oil lines as well.

How do I check if the oil in the coolant? I don't see how you would do this unless you drain coolant which is PITA in 335 since you have to remove intercooler.

[JBax]

if it was head gasket you would be burning coolant and getting light colored smoke out the exhaust in addition to what syndicategt said

[JamesM3M5]

If there is oil in the coolant, you will see an oil slick inside the expansion tank.

You would be the first person I've seen on these forums with a bad headgasket, if that is the case. Typically the valve cover gasket is the first to leak oil onto the exhaust.

[s2kman]

Thanks guys, I will get inspection mirror and check it in couple of days. Hopefully it's not HG.
Will report as soon as I find the answer.