I just purchased a 96 D1 today and it runs hot. The p.o. wasn't much of a car guy an parked it after started to run hot. Thinking it was a thermostat switch he po changed it ( might be bad or wrong temp maybe?) There is no coolant in the oil which is a good thing. I was thinking that the radiator needs to be flushed but don't know. When the car starts to run hot I turn the heater on to the highest setting and it will drop the needle to the middle of the gauge where it should be. It also will run fine for about ten minutes and then just start to climb until it gets near the red mark. I have driven it on the freeway and had the same thing occur, it would run fine for about ten minutes and then start to get hot all over again. Any help would be great.