Little to no A/C at Idle

[David Kriss]

I assume the fans are working and the AC is properly charged. Go get a can of HVAC coil cleaner. I bought a can for less than $10 at Home Depot. Give the condenser coils a good cleaning. I cleaned my wife's condenser this past Saturday and again yesterday. It made a big difference. You should also check and/or replace the cabin air filters. It doesn't take long for them to get pretty nasty and reduce air flow.

 

[ComoYukonXL]

Thank you all! So should I just try and top it off or take it in? We live Columbia Missouri and it’s crazy how much difference it is when you are moving.

 

[TahoeFL2017]

Hello all, we just purchased a 2018 XL SLT with 14k miles and love it so far, however when we are at idle, (stop light, sitting, etc) the A/C doesn't seem to be that cold. That being said, when we drive off, it is freezing. Is this something that GM has done for fuel economy? Or should I check a few little thing here and there or take it into the dealer.

All help would greatly be appreciated.

Thank you,

Matt

I recommend taking it to the dealer ASAP, with 14k miles its under warranty, and my 2017 LT is ICE COLD at idle in Tampa FL, where its 92+ by 9am , everyday until October.

AC in mine was leaking from the rear evaporator, but there is also a problem with the condensers on these trucks, that's why GM extended that part out to 5/60 warranty. If your low on Freon, INSIST that the dealer find the leak, its a sealed system, if you are low, its leaking. Most dealers won't check the rear evaporator, per my GMC tech, that finally got my AC working correctly.

Again, idle speed should have zero effect, I auto start my truck as I am walking out of the supermarket, and its cold while I put the groceries in the back. All while at idle speed.

 

[petethepug]

Document, document, document. Buy a cheap digital thermometer from home depot, stick it in the dash vent when the truck is at the dealer, at idle. Make sure they document on the repair order that "a/c temp at idle is xx degrees after truck had previously brought temp down to desired setting. A/C will not bring down temp unless truck is moving".

If that is documented the dealer is on the hook to repair it when it completely fails. They can not come back and state they drove the truck and could not duplicate the scenario. You could even go a step further and tell them you want the high and low side pressures documented as well as the outside air temp and relative humidity.

With all that info, you can easily chart what the discharge air temp from the inside vents should be, even at idle. It's not rocket science, but it is science they can't refute. I had to actually write info on my own r/o before and have the service writer initial it to cya. If it comes down to that you know the dealer is setting you up to fail.