WARNING: This page is about a different car, the 2002 BMW M Roadster, 2002 BMW M Coupe, 2001 BMW M Roadster, and 2001 BMW M Coupe. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
When the main flow oil-filter cover is released, the oil flows from the oil-filter housing back into the sump.