‘21 Tahoe - Cold on Drivers Side, Hot Passenger Side

[nmcgrawj]

So the final verdict is in....

Turns out the dealer didn't know what was wrong. They reached out to GM and they told them they have seen similar failures before and it was GM that told them the core would be blocked. So once they got the part in, my sister dropped off the truck this past Monday and picked it up today. They say the tech was able to confirm that there were blocked passages in the core. The truck HVAC is running as good as new now.

My only guess is that the new design has separate airways through the core so that if one side was blocked, it didn't warm up. While her car was at this dealer, they got another one in with the same problem.

I hope they identified the manufacturing issue with the supplier and the replacement part she got is actually a good part. I hope not too many other owners have to go through the same thing!

 

[89Suburban]

So the final verdict is in....

Turns out the dealer didn't know what was wrong. They reached out to GM and they told them they have seen similar failures before and it was GM that told them the core would be blocked. So once they got the part in, my sister dropped off the truck this past Monday and picked it up today. They say the tech was able to confirm that there were blocked passages in the core. The truck HVAC is running as good as new now.

My only guess is that the new design has separate airways through the core so that if one side was blocked, it didn't warm up. While her car was at this dealer, they got another one in with the same problem.

I hope they identified the manufacturing issue with the supplier and the replacement part she got is actually a good part. I hope not too many other owners have to go through the same thing!

That's cray cray a blocked heater core hmm.....

 

[Doubeleive]

that is crazy and unless they made additional design changes then when this type of failure happens after the warranty period is up it's going to be one hell of a costly fix. whole dash has to come out to change the heater core. $30 part and $1000 labor or something like that.

***also very crazy that a brand new heater core is getting "partly" clogged up, that shouldn't happen unless there was some kind of contaminate in the system , makes you wonder what else is getting clogged up.

 

[nmcgrawj]

Yea I am interested to actually see the HVAC system box to understand better on how it can cause a hot passenger/cold driver failure.

Reminds me of the recall from Hyundai we were notified of on our Sonata. Cutting chips in the crank oil circuit holes eventually leading to the crank eating itself. Luckily ours didn't fail.

There must have been some production run that had the heater system (and hopefully not entire coolant system!) become contaminated and lead to clogging the heater core.

 

[CptnC]

So the final verdict is in....

Turns out the dealer didn't know what was wrong. They reached out to GM and they told them they have seen similar failures before and it was GM that told them the core would be blocked. So once they got the part in, my sister dropped off the truck this past Monday and picked it up today. They say the tech was able to confirm that there were blocked passages in the core. The truck HVAC is running as good as new now.

My only guess is that the new design has separate airways through the core so that if one side was blocked, it didn't warm up. While her car was at this dealer, they got another one in with the same problem.

I hope they identified the manufacturing issue with the supplier and the replacement part she got is actually a good part. I hope not too many other owners have to go through the same thing!

Just dropped mine off to dealer for same issue today. I hadn’t read this before dropping off, but they’re going with same approach…flush the whole system b/c of “restriction” in the heater core (all day job). I was thinking it was a temp sensor on the driver side or an actuator. I explained when both the driver and passenger controls set to same temp (sync or not) force the fan on high and cycle through the vent options. Out of that center console the left (driver vent) blowing cold, passenger right next to not doing what is should be at 79 degrees (hot). Pattern same for the front defogger and the footwells. So definitely all vents associated with the driver side not putting out the temp the controller says.

 

[Taurus5778]

I have a 21 Tahoe RST and this morning the only way I could get heat on the driver side was to turn it up all the way to 81° or higher on the control. I turned the truck off and restarted it....Now I don't get any heat no mater what I put the control on. I havent called the dealer yet but I will update this post when I find out more.