I don't know the oil changing history, it was bought used from a mercedes dealer, Dealer said not covered by warranty because MB says its normal for thier cars to burn 1 qt. per 600 miles and they were not going to attempt any repairs because it was not covered by the warranty. Dealer directed me to call MB wjich I did and was told they were going to back up the dealer so no deal. Called the dealer agaign and they told me to WRITE to MB and see what happened. I did that with no results. Called the dealer again and they said to pick up the car which I will do this Monday. The dealer thinks this is a MB problem but that they are only following MB instructions. A good frien d of mine thinks theree are techinical service bulliten dealing with this problem having to do with a sensor and the head gasket. Can anyone HELP??? How can I find the service bulliten???