I have a 1999 Wrangler.. just bought it a week ago. The guy i got it from said it was overheating on him and thought it was the thermostat. I replaced the thermostat, housing, and radiator.. and have flushed the system several times. I had heat for a short period of time and the engine did mot overheat... however yesterday i drove about 5 miles and lost heat, and engine overheated. It was blowing anti-freeze out of the resivoir overflow... I'm at a loss for what to do next.. any suggestions?