I would suggest when you do the oil filter housing gasket to do both (no 4 and 5 on the sketch)
http://www.realoem.com/bmw/enUS/show...diagId=11_3971
If you'd like to know how to remove the belt, it is shown in this video of mine.
As for the video for the oil filter housing removal, I should release it any day soon...
https://www.youtube.com/channel/UCrf...f2b4-fZVKDUi-w