Shell Rotella is also available in a synthetic but the version most use is normal Dino. While different viscosities are recommended by Mercedes, depending on your climate, the 15W40 is good for all but the most extreme climates. Most listings consider the older Benz engines to be "hard working European engines" and recommend the diesel versions of oils for those gas engines. Many folks who have older Mercedes use nothing but diesel-rated oils. My 1990 300E with 98K has used it exclusively since nearly new and my friend has used nothing but that in his 1977 230 (gas) and with more than 160K. When the valve cover was removed recently for valve adjustment, everything was exceptionally clean!