Why is my heater is blowing cold air?


I changed the thermosat and it conitnues to blow air.


what model car? mileage? what has happened recently? any work, or accidents? more info is better.

does your radiator heat up? are the hoses warm?

if you do have heat in the radiator, then the pump is OK. but, are the hoses going to the fire wall warm? if they are warm, then the problem is likely a clogged heater core under the dash. try flushing out the heater core.


More information would really help. I don’t know if you have an air cooled 1970 VW bug or a 2005 Hummer.

Just off hand I would suggest a blend door problem, maybe mechanical or vacuum issues. You light look around for a loose vacuum hose.