Mechanics

HEATER

2002 Chevrolet Avalanche • V8 4WD Automatic • 300,000 miles

I have a 2002 Chevy avalanche 1500. I changed the water pump the other day and now the heater will not put out any warm or hot air. The blower works fine. The air conditioner work fine. The anti-freeze is at the correct level. Any ideas?
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Fcburrell
May 11, 2011.



With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

Wrenchtech
May 11, 2011.
I thank you very much for the reply. If there is air in the system, how can I bleed this out?

Tiny
Fcburrell
May 12, 2011.
A vacuum filler works best

Wrenchtech
May 12, 2011.