Originally Posted by StephenVA

So you searched in the ARTICLES and the HOW TOS above and you didn't find anything at all? If yes then you are the first to say so.
I know this will come as a shock but people have been posting the info you are seeking for YEARS on this forum. You are not the first to discuss this system which in BMW language is called an "oil separator".
Try a little reading effort in a few How Tos articles and then post.

Not trying overly to smack you too hard but you are making way too easy.

Tip: all that mayo in your breather tube is causing your system not to function as designed.