My 2008 535xi has an oil leak coming from the access/inspection window that is on the oil pan, directly beneath the axle passage. The plate is bolted to the pan with 4 torx bolts and the bolts (and therefore plate) cannot be removed without loosening/removing the front diff. What can I do to try to stop the leak?

 

I have an N52, but I have no idea what you are trying to describe and my car is reasonably similar.

 

Are you referring to the oil level sensor that is bolted on to the bottom of the oil pan? I'm not aware of an "inspection window" except for the opening in the aluminum support plate under the subframe that has a cutout in it for draining the oil. Is the part or the inspection window that you're referring to on one of these diagrams?

https://www.realoem.com/bmw/enUS/par...MW-535xi&mg=31
https://www.realoem.com/bmw/enUS/par...MW-535xi&mg=11