Heater occasionally blows cold air

02-18-2013, 02:16 PM
I own a 2002 Grand AM GT. With the engine temperature reading around 200, and the heat set at maximum, frequently, for about a minute, I will get nothing but cold air. At maximum heat setting, on one day, there would be hot air. Yet, at another time the air output would be lukewarm.

02-18-2013, 04:24 PM
You probably have a restricted heater core. what you can do to help this is to remove the return hose from the heater core and the sending hose of course and put a garden hose to the return to reverse the flow and keep doing it until the pressure feels like it suddenly realeased or untill the water comes out clear

Tech II
02-19-2013, 08:02 PM
In addition to a plugged converter(should check for a temp difference between inlet and outlet hoses), could also have an air pocket forming due to a leak? Check rad and reservoir level when cold?

Also check operation of temp valve actuator....

02-20-2013, 08:19 PM
I think Tech II meant heater core, not converter. :D As he said though, check fluid level when cold.

And yes these suckers are a B* about getting air pockets in the heater core!
Either from low fluid or what ever reason. :runaround:

Ive not seen many clogged. Well except for some fool that thought whole black pepper would solve a leak. which it did, but plugged up every orifice in the cooling system.

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