Heater wont blow hot air
 

hey i have a 02 civic and my heating system seems to have a mind of its own everytime i put hot air on it blows cold air and after a while it`ll go to hot air and so on. I checked the engine coolant is it the thermostate or something more serous any help will be appreciated thanks!

Re: Heater wont blow hot air
 

Have you checked your coolant level in the reserve tank/overflow? Have you burped you coolant system lately making sure all the airs out of it? Is the radiator full to the top? Have you overheated?

It sounds like you have air in your cooling system. If your coolant levels are normal then I would bleed the system and see of the symptoms return.

If the symptoms return you may be experiencing a head gasket failure. There are about 5 trillion threads on it by now. Do a search.