[335speed]

I took my 07 335i with 90k miles into my indy shop for a growing oil leak. I replaced my valve cover gasket yesterday and fixed that leaking but I still had oil pooling under my car after it reached running temps. According to my mechanic the leak is coming from an internal source and is visible at the right side of the crankcase. He showed me a bulletin about the magnesium and aluminum parts of the crankcase separating and causing an oil leak and insisted it was probably that. I was wondering if any of you have dealt with this issue before or if those symptoms can be caused by another issue.

[123Britt]

I did not think that the N54 was made with the lighter mag due to heat.
.
I would check the Bentley or other source -- I think only the non-turbo engines(N52) were made uising the 2 materials. Could be wrong??

[335speed]

Originally Posted by 123Britt

I did not think that the N54 was made with the lighter mag due to heat.
.
I would check the Bentley or other source -- I think only the non-turbo engines(N52) were made uising the 2 materials. Could be wrong??

The bulletin says its for the n52 n51 n51k engines so id be inclined to believe you. I cant even find the bulletin online. it is bulletin SI B 11 08 09 in case anyone can pull up more information.

[raceyBMW]

N54 has a plastic/composite valve cover and 100% aluminum blocks with iron sleeves, no magnesium to be found on the N54, so your mechanic is wrong. It is very likely that the leak is coming from the oil filter housing gasket that separates it from the block.

Are you sure its oil? If you have Auto tranny, then it could be the mechatronic sealing sleeve leaking, its known issue.

[F32Fleet]

The N54 is an aluminum or Al-alloy block. 100% sure on this.

[335speed]

Good to know about the composition of my block. Thanks for that good to know I don't need an entire crankshaft. I took it to a BMW specific shop, biggest I've ever seen. Told me they were pretty sure it was the oil pan gasket leaking. Thanks for the follow up guys.

[Red_Bean_Bun]

+1 on the oil filter housing .......

Originally Posted by raceyBMW

N54 has a plastic/composite valve cover and 100% aluminum blocks with iron sleeves, no magnesium to be found on the N54, so your mechanic is wrong. It is very likely that the leak is coming from the oil filter housing gasket that separates it from the block.

Are you sure its oil? If you have Auto tranny, then it could be the mechatronic sealing sleeve leaking, its known issue.