It's in a cast metal housing with a plastic cover. Should be able to unscrew it by hand if you try hard enough. Also it's a "O" ring seal not a gasket so there is no reason to overtighten.

 

rubber strap is perfectly good. Hand tighten is fine when you put it back on.

 

Thanks evereyone for all of your input but I still want to buy the proper wrench and not have to pay an arm and a leg. I've counted the flutes (16) and measured as best I can and it appears to be 86mm (although I've seen 86.5mm versions). It appears it is the same wrench that the E90 3 series uses and most newer Volvos. Can anyone confirm this - surely someone on the forum has purchased one of the lesser expensive versions? They are available on Ebay for around $8.00 plus shipping. The cap says to torque to 28.5 NM and I would like to be able to do this if I'm going to go to the trouble of spending $50 on the oil and $10 for the filter so I can change my own oil more often than 15,000 miles, which I think is way too many miles (and more than once a year for me). I've heard it from BMW techs that this long an interval is a BMW ploy to not have to give away too much free service and that they are aware that it can cause problems when your car starts to get higher mileage. I have friends that swear on trading in their Bimmers when they go out of warranty...

 

really quick the canister size in 36mm

 

Bavauto.com has the right one!