I was driving my stang and everything was fine, nice and warm inside then parked and went inside. then a couple hours later I go for a half hour drive and My friggin tempeture gage went all the way up to the red and the whole time my car was blowing cold air out the vents.What the hell was wrong with it?? Then about 1 hour later i left again and the car warms up in like 5 mins inside, and the temp gage back at normal. Could my thermostat be screwed?? i also checked the coolant and the resevior was almost full and i dont think its suppose to be is it??Is something clogged or what should i look for?