heater blows cold air when at idle even when temp is at normal?

The device known as the thermostat is supposed to let the engine warm up, then as soon as the coolant reaches 195 will open up and let the warm coolant circulate thru your heat exchanger...if it never gets up to 195 because it is stuck open, you will have minimal heat, just as you describe....in summation, change the thermostat and all will be skippy in skippy town.

...also 195 is operating temperature...if it never gets there you'll have incomplete combustion, resulting in smokey exhaust and poor acceleration...if you didn't notice.

be sure to have your mechanic 'belch' the heat exchanger or it will become air-bound after the thermostat replacement.

The dampers for the duct work of heating systems are controlled by vacuum. If at idle and car is at operating temp with heater on and you feel air coming out the vents but its cold and without touching any controls you start to drive and warm air starts coming out of them I would check for a vacuum leak going to the controller. As you drive faster the vacuum increases and will provide enough pressure to move the damper but at idle with the vacuum leak not enough pressure there to move it. This vacuum line will be coming from the intake thru the firewall to behind your heater controls. This is what I would check after you check all of what bob stated. Have to have heat in the heater core first.

Same with my 05 Impala. I changed the thermostat after it started blowing cold air. No improvement. I bled the brass bleeder on top of engine, filled resevoir, etc. It gets warmer the more gas you give it, then when letting off gas goes cold again. Both hoses to and from heater core get hot, so I am at a loss...

I am having the same exact problem in my 05 Grand Prix... going to change the thermostat tomorrow.

My car is always doing the same thing. Blows hot air until I stop. is this a Chevy thing or what? I have a 2007 Saturn aura, same as a Chevy Malibu .

I wish I new what was going on. I changed my thermostat, radiator, radiator cap, anti freeze, and I still have the problem. At idle, its cold air. driving down the road, warm air. I have a 1995 Mitsubishi Montero SR that I purchased new. A great machine, but this is puzzling.

I've been having the same issue with my 2007 impala. Done many coolant flushes and replaced thermostat. Recently had it flushed again, heater was working for about a month now it's blowing hot air only when I'm hitting the gas. Been having this issue for two winters now. My mechanic has no idea what's going on. thinking about replacing heater core? Any suggestions?

I fixed this issue for good in my grand prix. What it is is the coolant isnt being filled properly. Try running the vehicle for 5-10 minutes with your radiator cap off, and after it has been circulating for a little bit, fill it with coolant from the open cap and allow it to fill up your coolant container. This will flush out your bubble and solve you problem. At least it di for me...

I took mine in. It was a blown head gasket. Thank god it was still under warenty. It would have been close to 2 grand

I have tried several things on my 07 Impala. Total tune up including new thermostat. Nothing. Just had the heater core replaced, still no hot air when idling. Not over heating so no water flow problem. I will try the radiator, cap off while idling, adding coolant directly to opening and see what happens.

I changed my thermostat n my 2009 impala and done a flush and then my car started to do right on heat

This problem has happened on all 3 Impalas I have owned. It is none of the problems listed above---The engine coolant cross over pipe and gasket needs to be changed. Chevy has had problems with this for years. There currently is a new design that plugs the hole, but not so for the older models. The part numbers are 000000000012623852 and 000000000012623853 and 000000000012346290. The parts cost around $50.00.

I have the same heating issue and have done all of the above. I believe this is a Chevy issue that they need to do a recall on.

I'm not sure if they have done a recall on this, but there has been bulletins on it. You can ask your dealer to pull the bulletins. My car is by far no longer under warranty, but each of the previous times it has been covered under warranty.

I have owned two 2007 Impalas and both had the problem with going cold at idle.My mechanic found out there is a high spot in the radiator hose that can hold an air pocket.He does a procedure with a funnel in the radiator while it's running to get it out.I believe it has some kind of a seal at the funnel so the coolant can be higher than the air pocket

If it was an air bubble in the system the heat gauge would fluctuate when the bubble went through the motor wouldn't it? I am having this problem with my 07 impala what should I start with to attempt to fix it

I have a 2001 Chevy Impala .I had the problem with cold air blowing at idle. I took off the radiator cap and filled the radiator to the top and got rid of the air bubble. I filled the reservoir to the line now I have heat on idle. that fixed my problem. I wish everything could be this easy.

2007 has a actuator right behind the glove box. It regulates the amount of heat the heater puts out. this is usually the problem with the heater.

Wife started the Impala this morning and had no heat. Blowing only cold. Of course with the temps in the twenties, she wanted me to fix it. Mr. non-mechanical, can change oil and tires only kind of mechanical. After looking this column up, I added water to fill the radiator all the way up (only took a few ounces directly) and filled the overflow reservoir almost all the way up (it was empty). I started it up and it began blowing hot air with a minute. So, Mr. non-mechanical is a hero. Thank you guys!

Fill reservoir all the way up, while the car is off remove coolant cap on the passenger side fill with water, once full squeeze top radiator hose at highest point, release squeeze release squeeze as water recess fill it up again re squeeze release squeeze as you do this you notice air bubbles come out as you squeeze re fill keep repeating until it's full and no big bubbles when you squeeze then with the cap off start the vehicle and pour water in as it over flows for about 3-5 sec. Then screw cap on. Turn the heater on wait for about 1min then press the gas petal and try to hold it at around a thousand rpm on and off about three times and heat should be blowing out really hot by then.

@Thomas Youre logic was definitely in the right place....but if the weather is freezing temps or below there then please have your coolant tested to ensure it wont freeze now that all that water has diluted it. I had to "burp" my system this morning after a flush 3 days ago and inconsistent heat. Finally had the time to attend to it and get all the air pockets out. I used more antifreeze/coolant rather than water. Hopefully you see this in time and check. If temp gets lower than freezing point of your antifreeze/water it will crack your engine block causing catastrophic failure. Good luck and cheers.

I did use 50/50 antifreeze, now I am getting intermittent heat. If I'm driving in town and slowly, I'll have heat. If I'm on a highway and driving fast, then no heat. Do I need to change the thermostat?

hi i have and 2010 impala and mine was doing the same cold until driving then loop warm but i also say its running hot so i changed the thermostat and yet its still blowing cool while sitting and loop warm while driving and saying running hot any help with this problem

I have a 2003 Chevy Malibu. I've been having heat issues. The car temperature gauge is at the halfway mark, but the heat is COLD. I have to turn the heat off and then back on a few times for the air to get warm. Is that a thermostat issue?

Had same problem, it started after I put a water pump in. I just needed to purge/bleed some more air out.

05 Chevy Impala blows cold air from both sides. There is NO ticking noise. I changed the thermostat, took off the radiator cap, filled with antifreeze and watched for air bubbles. Then I replaced the cap and filled the overflow. Ran the engine to normal o.o temp and still no heat on either side. Tried driving it for awhile still blows cold.Checkef fuses for driver/passenger and replaced them. Still cold. Bought a air door actuator from AutoZone tonite and will replace it in the AM. I usually do small step to big step. I am stumped. Help. Rob

For the last 5 of it sounds like your heater core is plugged partially. Need to do a coolant flush and clean out the system. That's step 1. If there's gunk in there, and these models are known for it, when driving coolent flow is high and will get through to core and you have heat. If her arteries are clogged, when idling the flow is low and wont make it through heater core...no heat. Your fan pulls heated air through your core from outside and brings that heat to you. If your engine temp gauge is where is usually is(not overheating/engine shutdown mode) around halfway, your engine temp is fine. Thats what thermostat controls. The problems lies in getting that heat transferred from engine to inside via coolant, heater core, heating fan, then your vents. So start with flush, then heater core remove and clean or if too bad replace it. When new coolant added back in fill it, start car, let er bubble. Fill more let er bubble, squeeze hose lightly ro help bubble air out. Then cap once full and no air. Should be toasty after that. Sorry for late reply. Been super busy. Hope this helps. Over had a few impalas for the last decade and I do all my own work

Has anyone ever hear of the term Back-Flush? Look it up and do that to your heater core along with a full coolant flush and thermostat. Worked in my 05 LS.

Just did it on a Chevy Impala 2007 but with antifreeze and solved the problem, exactly as VInce said above: "Fill reservoir all the way up, while the car is off remove coolant cap on the passenger side fill with water, once full squeeze top radiator hose at highest point, release squeeze release squeeze as water recess fill it up again re squeeze release squeeze as you do this you notice air bubbles come out as you squeeze re fill keep repeating until it's full and no big bubbles when you squeeze then with the cap off start the vehicle and pour water in as it over flows for about 3-5 sec. Then screw cap on. Turn the heater on wait for about 1min then press the gas petal and try to hold it at around a thousand rpm on and off about three times and heat should be blowing out really hot by then."

I also have a 2007 Impala (flex fuel), and when I added more dexcool and squeezed the hose, I got a ton of air out of the system. Since I don't know what I'm doing, I followed a video and added coolant a few times with starting and revving the engine in between. I ended up using most of the gallon I bought. I don't know if this will solve my heater issues yet, since I won't be driving it for a little bit, but it definitely needed more coolant. Yikes.