Any oil leaks, say around the VCG?
My guess is if you have enough of a leak (would have to be big), it can drip down and MAY be entering via the hvac etc.
As far as the build up, best to see if it is affecting the breathing system (choking), sometimes if left long enough you will need it done. Start by using a good enough flush before your next oil service and see if it "helps".
Just a couple thoughts.
Last edited by Blackedout95; 02-27-2014 at 08:40 PM.