I have a 2006 Chevy Equinox that is getting no heat below 1500 RPM's. It had a new heater core and the mixing door replaced in late 2013. It work fine until earlier this year. it started off getting cooler not as hot as above 1500 RPM's to were I am now with no heat below 1500 RPM's. I am not leaking coolant and the system does appear not to have air in it. I did hear about water pumps having corroded blades which can cause this problem. I'm looking for advice on this problem and if I am going in the right direction replacing the water pump? The A/C did work good all summer but I need heat now, it's cool here in Indiana. Thanks

 

I suspect a thermostat is not sealed closed tight enough. Is the engine temperature normal?

 

Hi Bern, It looks to be normal but I guess I am not sure what normal is. The gauge needle is between the first and half way mark more to the half way mark. I have not had the Equinox long and that is where it has always been for me.

 

if you have no heat at idle and heat at 1500 rpm; air in the cooling system is the most likely cause. the water pump forces more coolant through the heater core at higher rpm. the core is designed to create a slight restriction to flow for better heat exchange.

I have dealt with this many times on U vans. I partially drain the system and then vacuum fill it.


Alternatively, you could fill it and open the bleed valves...then do multiple thermocycles but who has that kind of time.