Intermittent A/C

[AngeloUCF]

I found my invoice. GM bulletin N212340500. Notes say AC system was overcharged and that caused the issue. Again, I don’t know if the fix worked. This was done in October 2022 and I sold it in February 2023.

They told me the same thing when I took it in on Thursday but it’s doing the same thing today so it might have to go back.

 

[K5-Z71]

Same fault noted in Houston on a 22 model, cooling effectivity is reduce when cornering or braking hard. Dealership had the truck 5 days and advised pressures are all correct and system is meeting GM published cooling targets. They recalibrated the blend door and also advised that in automatic temperature mode the system will go warm at moments to keep target temperature... duh. Its clearly not a blend issue in my truck as I can smell the humidity coming off the evaporator when the degraded cooling occurs. My theory is that there is too much oil in the system which makes its way into the expansion valve when the vehicle is cornering or stopping hard which would greatly reduce the systems ability to cool.

I understand its difficult to get a tech to believe you about an intermittent problem and even more difficult for them to replicate the issue during troubleshooting but to do effectively nothing in five days is annoying at best. Off to a hopefully better service dept who will actually follow my instruction to evacuate and charge the system to spec. If that doesn't fix it then I guess Ill just have to accept its a poorly designed system like several others in this series.

 

[jjobev]

Has anyone found a fix for this? I have 2024 Denali and it is doing the same thing. I noticed driving around town today and the air felt humid and at times blows hot air. Not the first time but it was prominent today and I was paying attention to it. Then after running an errand I noticed the AC was like ice on drive home. I have played with taking off of auto and turning to low and manually putting fan on hi.

 

[Sean Michael]

Bump because I have the same issues. AC runs nice and cold, but sometimes it randomly blows warm air for about 30 seconds, then starts blowing cold air again.

 

[Footankleg]

Same problem here. 2018 Yukon Denali. Dealer had numerous times. I had to rent a car several times. They kept saying that they found a problem and kept replacing components. I spent a bunch of money and no change. They always stated that they could not reproduce the symptoms. The worst story from Chevy dealer was that “the engine would stop cooling until it had more power during driving”! I reminded him that this was a 6.2L V8 and over 14v. I had a 1.6L 4cyc that would freeze you.