[Heiko]

If at one point or another a bunch of oil got sucked into the overflow channels and filled the AOS to the point of oil getting into your intake, it could take a while to get it all out. If you had the car up on jacks in the front, the pooled oil in the intake could have shifted which will now take a while to burn off. If you can, take the cross tubes off on the intake and clean the TB as well as the intake bodies (it wont hurt anyways) and then watch it for a while to see if oil builds up again in the intake. I had a similiar issue a while back on a car and one of the oil return pumps went belly up.
H