its a 00 si with 65k on it. the problem is, when its cold out side and i have the climate controld set to OFF and the car warms up then i turn on the heater and it blows hot air but it will only blow hot air for a short time then it gets a little chilly. Is this cause the thermostat is bad or is it something else. its like i have to keep it off so it builds heat then turn it on shortly.

Any helpful answers will be greatly appreciated!!!

Thanks
Andy

 

No one has any ideas???? Im in colorado and its starting to get really cold in the mornings