Here's another thing to consider. If you have a/c, the radiator may be blocked by years of bug guts and leaf debris in between the radiator and the a/c condensor. With the current symptom you're describing it sounds like that may a contributer. Either that or there is some restriction in your radiator. Once you start moving your temp should go back down the M reading your started out with. If it doesn't then that is a sympton of what I described above. If your radiator is blocked in between it and the condensor, the only way to really clean it is to remove it and back wash it from the engine side forwrd. Doingit while it is still in the car will only lodge it in to the condensor.
