So I have I really wired issue with my 09 TC. About a year and a half ago I had a small amount of heat from my car on cold days. Yet the car was warming up fully to about 187 to 193 fer. About 87 to 91 deg for us Canadians. I eventually got tired of not getting good heat out of the car. Now don't get me wrong. It does but out heat. But its mediocker at best. My wife also has an 06 cobalt 4 door base model. That thing can sweat you out of the car in no time at all. If you hold your hand in front of her heater within 15 sedonds its burning your hands. Lol... Mine... You can hold your hand in front of it for days. Her heat according to a digital thermometer is about 80+ deg coming from her vents. Mine was about 55 to 60 deg. So a lot less. So I finally replaced BOTH my thermostat and my heater core. They were both gm parts right from GM. The heat after that worked great. It was almost mid to high 80s from my vents just like in my wife's base model cobalt. Well that was only a short one and a half years ago. And my car is back to putting out what i would consider low heat. I would say back into the mid 50s or low 60s again. I have no idea what it could be . I will say that my car NOW seems to heat up and run around 186 to 192 fer. About 86 to 90 deg. Depending if I'm coasting down a hill or going up one. Lol... Yet my heat is no where near that temp from my vents. And lastly. My cars hvac seems to be putting a fairly stronger air flow to the side vent up against the drivers side door then the center vents. Any ideas why my car would be running at pretty much the right range but my heat be so low. With a tstat and heater core that are only 1 1/2 years old. They would even be 2 years old until this April coming.

Thanks for reading my long story and any input would be great.

 

This is a strange problem indeed. I'm pretty sure the heater core should have fluid running through it even before the T-stat opens. You could maybe have a kink or something else partially blocking off your heater hoses that connect to the t-stat housing. Have you checked those out?

 

I havnt looked at the hoses per say yet. But I was poking around under the dash where the heater core is and the hvac motors for the vents. And it feels fairly hot and I feel like my air flow may also be slightly restricted ? I really dont know what this cars problem is.

 

Could have low airflow but you should be able to tell that fairly easily. Have you checked your cabin air filter?

 

You might have some crud blocking flow. Depending on the miles and if the previous owner added a head gasket or block sealer.

 

Here's the infos.
https://www.justanswer.com/pontiac/4...ue-heater.html
Here's the part for it.
http://www.crateenginedepot.com/Valv...85-P50948.aspx

 

I have had the car for almost 7 years. Sense almost brand new. It has nevwr had any head work at all. Or engine work for that matter. No head gasket. But Idk what that would have to do with it ? Also... What type of crud and where at ? Blocking what ? I replaced the cabin air filter at the same time as the tstat and heater core.

 

So your saying I MIGHT have air in my system ? How... And from what ? And I wonder if I do. If I can get it out by squessing the houses and running it with the cap off for a bit...

 

In my experience the air bleeds out of the coolant system on these cars fairly easily. I wouldn't think that is your issue.

 

dexcool can get nasty after multiple years of heat cycles. I'm sure it's not the nice clean looking dexcool it was originally. When I say crud I mean any corrosion flakes or dexcool that has gelled up. For a few bucks you can get a flush done and that might help things at the very least it's not a bad idea for the system to flush it.

 

I'm so confused with what could be wrong with this heat in this car... 😌

 

Like Ecaulk said you may just need a coolant system flush. In my 98 Chevy 1500 truck it got so it blew no heat at all just cold air and all it needed was a flush to fix it. And there was never any sealer or additive of any kind added to the system.

 

Second trying a flush. Another possibility is your mixer flap is not functioning properly. I'd think that if you got good heat right after changing the core then that would point away from mixer though. Your symptoms are actually pretty much exactly the same as the previous car I owned. We live in the desert so a working heater is not as crucial as it would be for you. I also tried replacing the heater core, had short success but then back to cool air. I figured it was probably a blockage.