I drove my '22 C8 on a 400 mile trip; 200 on one day and 200 back the next. With 100 miles to go on Day 2, the A/C began to work at, estimating, about 30% efficiency. After I stopped the car for 20 minutes and restarted it, it was working. Ideas?

 

Make sure your dual-zone HVAC is synced. Press the SYNC button and ensure the little LED light is on, and that AUTO mode is enabled.

Never hurts to check your cabin air filter too; with a 2-year old car you're due for replacement regardless of miles.

 

Exact same thing happening on our 21 Z-51 we bought last week. Have notified the dealer and when we get home in September...she goes in the shop for a HVAC check up.
Frank

 

Kracka, I put it in the shop immediately upon returning from my 400 mile drive. They had it for 6 days and told me to come get it because they could not get it to duplicate the performance issue that I had. They checked filters, coolant, et al. Thanks for your suggestion!

 

Hi Frank, mine is also a Z51 . . . 2LT. I took mine to the dealership within 20 minutes of returning from my 400 mile trip. They kept it for 6 days and said they could not get the problem to repeat. Told me to "come get it." My warranty expires on December 1 and I want to get this identified and repaired before that happens! Good luck to you, too!

 

How did they check your air conditioners' performance? Once crucial test is to measure the temp of the cooled air coming out of the dash vents. I think, typically, a "good" reading is that the vent air indicates 50 degrees F. I think an even better data point is the difference between air temp going into the evaporator and air temp exiting the evaporator.

BTW: I've read that C8s going to Saudi Arabia, can be equipped with an extra radiator to cope with their extra hot temps. My C8 radiator knowledge..the base C8 has two radiators, the Z51 has three, and the Saudi Arabian versions have four. Be interested to know if this is not correct.

My hot weather experience. Drove my Z51 2024 for hours in the California Central Valley in exterior air temps of 105 to 108 degrees. Driving ~80 mph, the engine temp was 190 degrees or a little less, and the interior was very cool. Good temp performance.

 

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My 24 Z06 seems to be having 2 levels of performance. Sometimes feels cold and normal, sometimes definitely feels weaker or warmer. I have to remember to get some vent data, maybe hook up a set of gauges to it. Hate going to the dealer.

 

Two day trip for me out here in Arizona, did the last portion of the trip coming out of the mountains in Prescott with the top down, 75°. Perfect weather until I got down into the valley, Wickenburg area, over a hundred degrees outside so turned on the air conditioner and a few miles later put the top back up. Air conditioner began to degrade slowly, temperature was heating up and pressure out of the vents was dropping. Drove the last hour getting warmer and warmer out (outside temp 115).

The vents never stopped blowing some amount of air, and it was definitely cooler than ambient, but not enough to make a difference. A mile before the house, I decided to turn the air conditioner off, and just let the vent blow…(my wife is losing it at this point), it blew ice chunks all over the cabin, obviously the condenser had frozen up. It began to blow cold air again at this point.

That all happened in the first 500 miles of ownership. I have 1000 miles now and it has not occurred since but if it does, I will turn off the AC to let the condenser thaw out and keep on driving. No way will I let the dealer try to duplicate this. I chalked it up to an altitude differential from the mountains to the valley, approximately 5000 feet down to 1000 feet, not sure if that holds any water but that’s what I’m telling myself.

 

I have had a few scares since my incident (see my full response) but it always seems to get back to cold quickly.

 

I know it's not a Corvette but my BMW M4 (I traded on my C7) did this. The evap core actually froze up. Yours sounds similar as sitting for a bit lets it start working again. Mine was worse in higher humidity. It helped to set the temperature at 71-73. It was better than zero AC.

 

AC units have been known to freeze up in other vehicles.

 

Hello Kracka, I did sync the A/C after getting your suggestion. That said, I did have a passenger the day it demonstrably diminished cooling. Even though not synced, both sides were set nearly the same, I'm sure. Probably within a degree of each other and both around 70. Seems syncing, in that case, shouldn't make a difference?

 

I also have issues with my A/C. It can be ice cold one day but then the next it's barely cool enough to keep me comfortable. It can even vary within the same day. I can't figure out what triggers it or how to remedy it when it does happen.

 

I've only taken one long road trip in my car(600 miles or so) and it was a warm summer day with temps in the 90's. Air worked great on the first leg of the trip, but seemed to be barely working on the return leg. I drove over a hundred miles trying to figure out why the AC wasn't working before I just gave up and put the top down. The next day the AC was working fine and I haven't had the same problem since that day.
I wrote the incident off as a glitch. With 300 miles to drive I didn't consider pulling over to do a system reset. It would be nice to know if that would have solved the problem.

 

The couple of times it happened to me it turned out the button for the dash vents somehow got turned off.

 

Hard to see what's on/off on the wall of buttons with those tiny red light dots during daylight.
Wish they had used super bright LEDs. Easy to turn off the dash or floor vents by accident, hit the wrong button.
You could easily bump the mechanical dash vents airflow direction levers, and partially block airflow to the cockpit. I find them hard to adjust, very sensitive.
Also setting the temperature set points to something reasonable (70F -73F) as mentioned prior will keep the system from freezing up under stress.
My MB Sprinter did the same thing, and the fix was pick a more reasonable set point like 70F, don't just set the dial to the lowest cold setting.
Or, maybe the coolant simply needs a top up.
Good luck.