no heat

[cracker68]

I have a 99 pontiac grand am. That is not warming the inside of the car up when it is sitting idle. The only heat that I get is when I press the acelerator, then the warm are blows like mad, but once I let off it goes back to the same..blowing cold air. I changed the thermostat already and I am thinking that it is maybe the heater core.

any thoughts ...?

[doctorhrdware]

could be that the heater core is clogged or a weak water pump. That also would make sense too due the higher RPM's will circulate the better water.

[3100]

air pockets, bleed air from the cooling system

[doctorhrdware]

That is one thing that I forget, is the air pockets.