Automotive Air Conditioning Information Forum

Hello! I'm trying to find a leak on a 2009 Enclave, which takes about 6 weeks to 2 months to totally leak out all it's refreigerant after a recharge. I put an air compressor on the system to pressurize it to look for leaks, but could not find any obvious leakage. I left it pressurized at 125 psi on the high side and 65 psi on the low side. After about an hour the high side was down to about 120 psi and the low side was up to about 75 psi. Is that normal, or is that some kind of internal leak? thanks in advance for any info!!

wesdoobner wrote: ↑Thu Apr 07, 2022 5:42 am I put an air compressor on the system to pressurize it to look for leaks, but could not find any obvious leakage. I left it pressurized at 125 psi on the high side and 65 psi on the low side. After about an hour the high side was down to about 120 psi and the low side was up to about 75 psi. Is that normal, or is that some kind of internal leak? thanks in advance for any info!!

1. Both sides will equilibrate to the same pressure over time.
2. Not sure that it's a great idea to pressurize using air, as moisture in the air can overload the drier/accumulator pellets.

Professionals can use a variety of methods to find leaks: visual observation for residue, soap bubbles, UV dye/goggles, and electronic sniffer.

" Not sure that it's a great idea to pressurize using air, as moisture in the air can overload the drier/accumulator pellets."

Cusser, you got that right. Understated. Really bad idea. I would let the air out, puff in about 20 psi of refrigerant, and use an electronic leak detector sniffer to find the leak, including sniffing the drain tube of the evap. Refrigerant is heavier than air, so if the evap is leaking (they often do) it will accumulate in the drain tube.
Once you find the leak and repair, change out the filter drier, and get a good vacuum on there. You will probably have trouble getting a really good vacuum at first because the moisture content will prevent that. I would do a triple evac. IE pull the best vac you can, then charge in about 20 psi of refrigerant, then vac again. Then repeat once more time, then a final vac and full charge. This method will help to remove moisture.

Well I guess my next step is to pull the vacuum a few times, then try a dye injection kit. Can you rent a sniffer from one of the auto parts stores? I don't happen have one of those.

Usually underbody lines leaking on those GM Lambdas. The next generation Enclave/Trav/Acadia had horrible rear evap leaking problems, those 1st gen had rear evaps that leak too

Not sure you will be able to pull a vac if it leaks. Can try. Not critical right now. Just need some refrigerant. NOT a full charge.
Will def need to puff some refrigerant in there to use a dye kit
I am not aware of sniffers being rentable. We traded the dye in for a sniffer many years ago