2009 Impala, 6 cyl., 32k miles, with the engine warm and running below 1000 rpm I only get cool air entering the cabin. As soon as I rev up to 1000 rpm and above heat enters the cabin. The coolant level was a little low and I added about 2 cups. I haven’t driven it since adding the coolant but I doubt that is an issue. Since the day I bought this vehicle (at about 16k miles) I could detect a whine sound coming from the engine compartment at start up. This may have something to do with this problem, but until just recently the heater did work fine. The A/C works fine. Looking for suggestions of where to look. Thinking maybe a water pump?
I am thinking you have a coolant leak. I assume you mean the coolant level in the overflow cannister that has nothing to do with coolant in the system. You need to check the level in the radiator when it is cool. Better yet I think you have a warranty issue covered by the dealer, go there first if so!
If you’re adding coolant it means you’re losing coolant. And this can mean there’s air entrained in the cooling system. If so, when idling the water pump slows down the coolant flow enough where the air collects in the heater core and there’s no heat. When you step on the accelerator, the engine speeds up, the water pump speeds up, the air is forced out of the heater core and the heat returns.
If the vehicle is still under warranty, take it to the dealer and ask that they check for air in the cooling system and for a coolant leak. If the vehicle isn’t under warranty, take it to an independent garage and ask if they’ll do the same thing.
Tester
“If the vehicle is still under warranty, take it to the dealer and ask that they check for air in the cooling system and for a coolant leak. If the vehicle isn’t under warranty, take it to an independent garage and ask if they’ll do the same thing” for less.
Thanks Barkydog, Tester and JosephEMeehan…I never thought about air possibly being in the system, sounds reasonable to me…I checked the coolant level this morning with a COLD engine this time and sure enough it was below the line on the side of the reservoir again. I added almost another 2 cups. I’ll first discuss it with a dealership as advised…didn’t think it could be a warranty issue. I did buy it from a Chevy dealer but as a used vehicle. Thanks for your help.