I have owned several Mercedes diesels 1972,1977,1980 and one of the things I ran into was the recomended oil change interval. At the time I owned these cars the manual and dealers recomended 1/2 the distance for oil changes. The gas Mercedes recomended 6000 miles changes and the diesel recomended 3000 miles changes. The thinking was that diesels had more junk that would get in the oil and needed quicker changes. Is this still true today with the newer Diesels??