Little to no A/C at Idle

[ComoYukonXL]

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

 

[swathdiver]

Well, you can check to see if both engine cooling fans are coming on but beyond that you need a bi-directional scan tool to see what the AC actuators are being commanded to do versus what they're doing. If she's under warranty, let the GM dealership handle it.

 

[Bob2C]

Well, you can check to see if both engine cooling fans are coming on but beyond that you need a bi-directional scan tool to see what the AC actuators are being commanded to do versus what they're doing. If she's under warranty, let the GM dealership handle it.

Same thing with my 18. I noticed it the other day when it was really hot. It’s freezing cold when I drive so I assume it’s working but at a light not as cold. I bet it has something to do with fuel saving. Just like alternating voltage fluctuation.


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[BourbonNcigars]

Could depend on the outside temps. I don't have a Tahoe anymore but my current vehicle will do the same thing in the extreme heat we've been having in the Southeast. The fan can only do so much compared to the air intake from driving.

 

[swathdiver]

I don't have a Tahoe anymore...

I missed something, what happened to it? Wasn't that the Black-n-White?

 

[PG01]

Noticed it on my 19, a/c sucks at idle and is fine at speed.

Actually noticed while idling in a parking lot in Florida while on vacation waiting for the wife, I actually had to loop around the lot few times because i was getting annoyed, i even popped the hood to be sure compressor and fans were running.

Newer GM trucks at work do/feel the same, i actually had a mechanic at work capture and evac the system then refill according to the label under hood and it actually made a difference.

I have a feeling the robot at the GM plant decided to skimp on the charge to save a few bucks.

I will wait until the fall to bring my truck to the dealer, although I don’t have any faith in them so im still contemplating this.

 

[BourbonNcigars]

I missed something, what happened to it? Wasn't that the Black-n-White?

It was an SSV. Traded it a couple of months ago. Thought I could deal with the spartan nature of it but I was wrong. Doesn't mean I won't get another Tahoe in the future, but probably a '16 and up.

 

[Miami-Dade]

If I lower the temperature to 68 in gridlock conditions [which is very often here] the air stays fairly cold. Having the rear a/c on keeps the vehicle nice and comfy. At least for me anyway.

If you do not have tint on your front 2 windows [20% or less] and limo tint on top of your windshield near or below the ASE line [especially in the south] get it done.

 

[swathdiver]

It was an SSV. Traded it a couple of months ago. Thought I could deal with the spartan nature of it but I was wrong. Doesn't mean I won't get another Tahoe in the future, but probably a '16 and up.

Nothing wrong with the finer things in life!

 

[BourbonNcigars]

Nothing wrong with the finer things in life!

I like the irony here. Reading your reply as I enjoy my wine from a box...

 

[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.