I have 08 F250. It overheats in a strange way. First 100 miles or so, it has no problem and temp gauge is on the dead center. Then with in 5 sec, the needle goes to the far right and overheat warning is on. I stop the vehicle and then, even before I stop the engine, the needle goes back to the dead center again. It takes about 30 sec to 1 min. After that, I can drive as if nothing happened. Is this a real overheat problem or a thermostat or something is wrong?