so I am working through some oil separator issues. Very common as I have seen on this board, but I figured I would throw in my 2 cents, as well as add some information.
First of all, 2006 has a different oil separator than its 2001-2003 predecessors. I used procedure B on this form
BMW SIB as my guide
Symptoms:
rumbly squeel sound at start up. I thought it was cold belts.
rough idle after about 2 minutes
Service Engine light came on one time after I immediately started driving after starting cold car
Mechanic Diagnosis:
Running lean, several engine misfires
Cause:
Water condensation in pipes mixed with cold weather. I am in Spokane, WA but problem first arose after an overnight drive through montana with zero degree temps.
Mechanic wants $450 to fix, so I decided to look into the problems. All the parts are easy to reach and relatively inexpensive. At this point I have spent nothing on parts - only cleaning my existing parts, but I have ordered aftermarket valve caps and they were only $35 for a pair, shipped.
The repair:
Take of the Crankshaft caps carefully - pulling the tabs on the caps up and jimmying it until it comes loose. As of now my new valve caps have not arrived so I just cleaned the existing ones to see what kind of difference this made.
I also removed both hoses - you just squeeze the ends and they come loose. This can be a little difficult so I used a pair of channel lock pliers. The hoses were pretty clogged so I flushed them out, then cleaned with a rag and pipe cleaners.
After putting it all back together the rough idle has completely disappeared, but I still get the "ripping" sound on my first start of a cold morning. After a week I checked the cheese buildup and found some was returning. My next step is to completely replace the valves. This is an obvious step from the get go, but I only did the cleaning since I was waiting for the new parts.
Also, I did an oil change - Castrol Edge SPT 0w-30 GC seemed to be the most recommended oil for cold weather so thats what I went with.
I will update after I do the full valve replacement and see what that does.
Note: I know the updated system has the valves on the hoses. I may end up doing that complete upgrade, but for now, this repair is worth trying.