mercedessource Tech help - Quick list of things you can consider to increase performance and mileage Produced from 1984 to 1993 these lighter weight aluminum head engines replaced the venerable cast iron 616 and 617 engines of the 1970's and early 1980's. Theses engines were more powerful and more fuel efficient. They did have a few teething problems but have proven to be very durable as long ...By 1991 Mercedes had evolve the OM603 motor for greater reliability. If you want a more simple mechanical diesel engine this is the one to have. A great alternative to a Volkswagen Passat or Jetta Tdi wagon or other more modern BMW diesel or Mercedes Bluetech CDI. Drivetrain: Rugged OM603 3.0 liter 6-cylinder turbo-diesel. Recent Michelin tires.