These cover gaskets are a bad design. To add insult to the injury, it is NOT a minor job. It was changed under warranty once and now out, it needs to be replaced a second one in 65000 miles. My car consumes 1L/2200miles and I think that the cause is the seeping.
2007 E90 AW 323i Step | Lowered 1.25"/1" | BMW Performance Exhaust | PBX | Debadged | Scangauge II | Style 162 18" & 161 17" wheels & rear 15mm spacers