So I brought my "new" 350SD home today. A 30 mile drive, my first time driving it over anything other than the mountain dirt road where it lived. At 205k miles, the car drives and rides better than it has a right to! The power seems a bit sluggish, and I know it has an injector problem as it idles roughly but smoothes out under load, and cruised comfortably at 70-75mph on the highway. I am curious about operating temp on these cars. With an outside temp of 40f, the coolant temp stayed around 90-95c. What should it run at?