I am really hoping someone can help - garage seems baffled by the problem.
The car is 2003 and done 120k.
The symptom is excessive oil usage - i am talking about a litre every 500 miles or so.... It never used to do this. It came on fairly swiftly after fairly normal BMW usage.
I took it to the garage who diagnosed the oil breather system as being worn out and needed replacing, which we did.
I asked them to check compression - nothing unusual showing.
MOT same day - failed emissions before breather system change, afterwards all emissions ok.
BUT it still burns oil. You notice it when you've idling (stuck in traffic) and when you speed up, the smoke comes!
Garage thought this was because it's building up through the breather system and depositing in the manifold - they are saying the only two things it could be are the valve stem seals or the oil scraper ring on one or more piston.
I am no expert, but it seems strange to me that this would be the case... the sudden onset would be strange for either of these. If it were the valve seals, I would expect them to fail slowly, gradually increasing oil consumption. Do oil scraper rings suddenly break? I don't know - advice would be very welcome!
Really hoping I don't have to get rid of it - either seals or rings is too much to justify on the car so I am hoping one of you has some experience/ info.
Thanks in advance everyone!