Quote:
Originally Posted by wroom1
Here is the pic  oil leak is only on this side of the engine. Is there any ways to pull out this bolt? Not sure why BMW uses these alu bolts on engine block!!!  |
Yep, on the N52's you can get a nasty oil leak when that bolt breaks. It's actually one of the head bolts.
The reason for the aluminum bolts is that the N52 uses a composite magnesium-aluminum crankcase. Magnesium and steel don't work well together. There are some locations (transmission bellhousing, etc.) that use alumimum bolts but are threaded into the aluminum insert portion of the block. Why BMW didn't use regular steel bolts in these locations is beyond me. Possibly to avoid confusion as many of the bolts on the engine DO thread into magnesium.