Originally Posted by Exempt
Yea, but when u shut the car off for the night and it cools down, the thermostat is supposed to close... If it wont close when u first start the car it will be overcooled (since its still open)...
However it would eventually get to normal operating temperature, though it would take longer to get there. Since he describes driving for extended periods of time and experiencing overcooling, it's probably not the thermostat. If he drove 10 minutes accross town, then yeah, I'd guess thermostat.