Jump to content

Ac not keeping up

Aimatdeer
 Share

Recommended Posts

Aimatdeer Enthusiast

Aimatdeer

Posted
Posted (edited)

2024 l8t . Ac has never felt really cold even new. But lately it seems a little warmer. When it gets in the upper 80s and a little more humid it just does not keep up. And sometimes at idle it gets warm. My wife's 2008 envoy is better. My son's 2016 is colder. I have an apointment for a third try Monday the 29th at a third dealer to try and get cold ac before my warranty is out. The first two told me something about so many degrees under ambient temp blah blah blah seemed like they didn't want to mess with me. This was set at low. Max air fan speed high. 87 degrees and a little humid.

 

.

Screenshot_20260621_083754_Gallery.jpg

Edited by Aimatdeer
Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted
1 hour ago, Aimatdeer said:

2024 l8t . Ac has never felt really cold even new. But lately it seems a little warmer. When it gets in the upper 80s and a little more humid it just does not keep up. And sometimes at idle it gets warm. My wife's 2008 envoy is better. My son's 2016 is colder. I have an apointment for a third try Monday the 29th at a third dealer to try and get cold ac before my warranty is out. The first two told me something about so many degrees under ambient temp blah blah blah seemed like they didn't want to mess with me. This was set at low. Max air fan speed high. 87 degrees and a little humid.

 

.

Screenshot_20260621_083754_Gallery.jpg

AC in home or auto only cool down 15-25 degrees from outside temp, but what will help is to put the ac in recirc mode this will recirc the Inside cabin air rather then trying to cool down the outside hot air, I always have mine in recirc mode.

  • Like 1
KARNUT Senior Enthusiast

KARNUT

Posted
Posted
4 minutes ago, Silverado4x4 said:

AC in home or auto only cool down 15-25 degrees from outside temp, but what will help is to put the ac in recirc mode this will recirc the Inside cabin air rather then trying to cool down the outside hot air, I always have mine in recirc mode.

I call B.S. when I first moved to Texas my first house would only cool to 80 with the Texas heat. The AC tech said it was normal at 100 degrees outside. I remodeled the house put in a new AC. I could hang meat. My cars may need recirculating to start. Once moving it switches to regular AC and I could hang meat. Living in Texas no one would put up with only 20 degrees difference. 

  • Like 2
Byrds8 Enthusiast

Byrds8

Posted
Posted

Mine is in the shop for the AC now. While it did get cold after a bit, it would take a while to even start to cool the air at all. Turns out the compressor was bad and cycling. 

Aimatdeer Enthusiast

Aimatdeer

Posted
  • Author
Posted (edited)

I was using recirc/max air. Especially if it really hot i start out by lowering the front windows a little with regular ac the go to recirculation after a few and rolling windows up. And it does not have the newest refrigerant. It has per the info under the hood r134. Not the new r1234yf.

 

Edited by Aimatdeer
Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted
1 hour ago, KARNUT said:

I call B.S. when I first moved to Texas my first house would only cool to 80 with the Texas heat. The AC tech said it was normal at 100 degrees outside. I remodeled the house put in a new AC. I could hang meat. My cars may need recirculating to start. Once moving it switches to regular AC and I could hang meat. Living in Texas no one would put up with only 20 degrees difference. 

OK you say you could hang meat but what was the actual temp? One of the AC systems job is to remove humidity that we feel on our body your new system removed alot of humidity as that is were the water comes from on the ac coils and that made it feel colder. 80 degrees with high humidity will feel hot vs 80 degrees with low humidity will feel alot cooler.

KARNUT Senior Enthusiast

KARNUT

Posted
Posted
2 minutes ago, Silverado4x4 said:

OK you say you could hang meat but what was the actual temp? One of the AC systems job is to remove humidity that we feel on our body your new system removed alot of humidity as that is were the water comes from on the ac coils and that made it feel colder. 80 degrees with high humidity will feel hot vs 80 degrees with low humidity will feel alot cooler.

My house is set at 75. My car at 70. When I have guests the house is at 70. 

PunchT37 Enthusiast

PunchT37

Posted
Posted (edited)

That a/c has got a problem. It should be able to put out at least mid 40`s temp on a day like that. 
 

Vent temp, that is. 

Edited by PunchT37
  • Like 1
Atlas Senior Enthusiast

Atlas

Posted
Posted

Hard to say what the issue might be. Anything from the ability to cool the AC condenser up front, to blend door issues in the HVAC unit, to refrigerant charge, to compressor issues or issues in the lines.

 

Report back what the techs find on the 29th.

 

GM has service publications which list acceptable vent temperatures and AC pressures at given ambient temps and humidity. They probably won't touch the system if it's operating within those ranges.

 

I'm also surprised to hear your 2024 with the L8T is still using R134a? I was pretty sure the HD's had switched to the new refrigerant around 2020.

PunchT37 Enthusiast

PunchT37

Posted
Posted (edited)

If that guage has a way to adjust [hex on bottom], put that thing in a glass full of ice, put water in, put your gage in, let it sit for 3 minutes or so, and set it to 33 degrees.

Edited by PunchT37
Aimatdeer Enthusiast

Aimatdeer

Posted
  • Author
Posted

The thermometer has been in my wife's 2008 envoy, my sons 2016 chevy, my friends 2020 1500 silverado all showing cooler readings. It's not the guage.

asilverblazer Senior Enthusiast

asilverblazer

Posted
Posted
20 hours ago, Atlas said:

Hard to say what the issue might be... to blend door issues in the HVAC unit...

My 2008 started exhibiting similar symptoms, wasn't 'cold' enough. I went through a pretty extensive diagnostic process for a DIY'er with limited OBD access. System evacuation and recharge included.

 

Noticed one day the passenger side was cold (I'm never over there so took awhile to notice).

 

Pulled the drivers side blend door actuator out, disassembled it and cleaned it out. Put it back in and did some kind of reset and it fixed the problem.

 

Long story short, it wasn't the A/C system at fault, the blend door wasn't moving to full cold position. 

newdude Senior Enthusiast

newdude

Posted
Posted (edited)
On 6/21/2026 at 8:38 AM, Aimatdeer said:

2024 l8t . Ac has never felt really cold even new. But lately it seems a little warmer. When it gets in the upper 80s and a little more humid it just does not keep up. And sometimes at idle it gets warm. My wife's 2008 envoy is better. My son's 2016 is colder. I have an apointment for a third try Monday the 29th at a third dealer to try and get cold ac before my warranty is out. The first two told me something about so many degrees under ambient temp blah blah blah seemed like they didn't want to mess with me. This was set at low. Max air fan speed high. 87 degrees and a little humid.

 

 

 

 

Seen this gen truck with bad compressors.  Also bad blend door linkages which requires replacing the entire HVAC box, but those ones are for getting two different temps driver vs. passenger side (cold on one, hot the other).  

 

 

EDIT:  Performance chart with MAXIMUM outlet temperatures.  So depending on ambient temp and relative humidity, you should see temps no higher than the column on the far right out of the vents. 

 

So @Aimatdeer if there are no leaks, the charge of refrigerant is correct, and everything is operational (compressor, temp doors, clutch fan), it might be on the high end of normal per this chart.    

 

Screenshot2026-06-22150106.thumb.png.e0ac6c54be37e6100a45baec4538231a.png

 

Edited by newdude
AndrewF Enthusiast

AndrewF

Posted
Posted
1 hour ago, newdude said:

 

 

 

Seen this gen truck with bad compressors.  Also bad blend door linkages which requires replacing the entire HVAC box, but those ones are for getting two different temps driver vs. passenger side (cold on one, hot the other).  

 

Even on a hot/humid day, vent temps with a thermometer should be 40-50F coming out of the ducts when set to the coldest temp.  

Is there a spec on what temperatures are acceptable vs. not acceptable?  My '24 has fairly weak AC as well but I don't want to waste my time or the dealers time if it is still in spec.

newdude Senior Enthusiast

newdude

Posted
Posted
32 minutes ago, AndrewF said:

Is there a spec on what temperatures are acceptable vs. not acceptable?  My '24 has fairly weak AC as well but I don't want to waste my time or the dealers time if it is still in spec.

 

 

Just edited my response with a performance chart I found.  

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,759
    Total Members
    8,960
    Most Online
    DM22
    Newest Member
    DM22
    Joined

  • Who's Online   1 Member, 0 Anonymous, 3,047 Guests (See full list)

  • Latest Articles

  • Posts

    • asilverblazer
      Transmission Woes :-(

      By asilverblazer · Posted

      Yep, just a quick reference point.    My main point being I’d do a thousand other things before I’d pay 10k for a transmission.    Speaking in ignorance cause I don’t look at these trucks, what is it worth? 20k?
    • asilverblazer
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By asilverblazer · Posted

      I think users are going to want to pick their monitored parameters, which parameters they want to see first.    It should probably start with baseline at a minimum and adjust to learned, but be able to overlay baseline for comparison.   A simple severity level would be able to determine what type of alerting is appropriate or user selectable.    Why not use the OBD port though?   I think a phone connection would be a good idea, push notifications type deal.   Number 1 issue is having data is useless if you don’t know what the data should be under normal conditions. 
    • Chuck FB
      summer road trips in the 2026 2500HD

      By Chuck FB · Posted

      I thought I would use your thread and add to it as I just did my first longer drive with my truck in the last couple of days. I drove from the Grande Prairie area of Alberta down to Edmonton and most of where I drove in the city was the ring road so fairly free flowing but a bit of stop and go as well in the city. Stayed the night and returned home and not too many stops along the way each way but every restart and certainly every cold start sets it back for fuel mileage. Why I say that is I see some people will cherry pick a fuel mileage leg after the vehicle had been warmed up driveline wise before hand and its a forgiving ( easy rolling drive leg for example ) and call that their fuel mileage which can give a false perception of reality. I was not heavily loaded at all but never the less the flip bak cover, rubber bed mat, various tools etc and extra jerry cans of fuel all way up to a few hundred pounds of dead weight so its not an empty truck. The cold inflation tire pressures are set more near the freezing point so once they are warmed up driving I was showing 45 front and over 40 rear and realize high inflation pressures would help a little in fuel mileage but certainly not the ride on our crap sections of highway. The weather was good so was not raining as that can really drag mileage down, in fact I had a bit of a tail wind on average driving home. Most people on here would never have driven on that freeway to visualize it but its got a fair bit of rolling type of landscape with numerous river valleys. For the most part I had it on cruise set to 62 although kicking it off if I caught it in time before it started down shifting and self braking going down the grades. Most of the more substantial grades its shifting into 7th I believe as 8th just doesn't have it. Total distance round trip was 643 miles and my overall average and I did refuel three times in all, figured out to 17.65 miles per US gallon. My best fuel mileage section refuel within all of this figured out to 18.46 and these are all hand calculated figures. I find if anything that the trucks computer can be over optimistic, sometimes its pretty close but other times its stretching it. On paper persay in theory the truck would have just about made it on fumes for that whole drive without refueling once.    Which made me think of the topic thread of the wonder if these trucks could do 20 mpg and that is a good question, certainly would have to be on an easy going flat highway, no head wind, the right temperature, not packing around a bunch of dead weight and puttering along even slower than I was I would suspect and going steady and not stopping to smell the flowers or take a piss !. It probably is possible but not without effort to attain that with the wind resistance and weight of these trucks. Of course on my drive most people are passing me if they have the power as per loaded highway tractors, never mind a lot of speedy vehicles but the speed limit is 68 and most are at or well over that. 
    • Aimatdeer
      Ac not keeping up

      By Aimatdeer · Posted

      Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      Paid $2.72 for E85 today.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...