AC Leak - Pulling my hair out.

[Alex_M]

Hey all! Need some help from someone more experienced with AC work. I have a refrigerant leak that I cannot find. It leaks out every 12-24 hours, so I've been living without air for the most part. I've put UV dye in; couldn't find anything. Put a double shot of dye in; couldn't find anything. Hoping it were a small leak since I couldn't find it with dye, I tried a refill with stop leak. No change, didn't even seem to slow it down much if any. I replaced the high and low side valves, no change. I purchased a sniffer, put a charge in, and I've been going over it for the past hour. Every line, every joint, all over the condenser, around the compressor, in the vents, under the dash, everywhere. The system lost about 5psi while I was searching with the sniffer but I cannot for the life of me find the leak. I did confirm the sniffer works with a controlled leak out of my gauge set.

One piece is that after I have charged the system, if I walk by the passengers side of the truck in the evening I can smell the refrigerant so I expect the leak is somewhere in the engine bay, not under the dash. I am trying to avoid replacing everything just to start fresh, but that is nearly the point I have reached. Any input on better testing methodologies or likely spots to check I may have missed, I would be greatly appreciative.

 

[BattleTank]

Start the engine, run the blower on high and turn off RECIRC. Run a garden hose of water into the vent at the bottom of the windshield for 10 seconds. Shut the hose off. Observe the water coming out of the drain hose on the firewall with your UV light. Any signs of green in the water?

 

[Alex_M]

Having trouble finding my UV light now. Lets assume the answer to that is yes (will confirm once I find the light). What would that point to - evaporator?

 

[BattleTank]

Correct. If the evap was leaking, the dye would be stuck to it, depending on how humid your environment is. Introducing water into the duct system should wash off the dye and flush it out the drain tube.

 

[OR VietVet]

How are you checking for the dye leak? Eyesight only? With a UV light? Have you never noticed where a/c oil would leak out and leave a wet spot? Seepage at the compressor is hard to find sometimes and refrigerant is heavier than air. If you check at connections/seals areas, check at the bottom. Sure sounds like a leak at the evaporator, like @BattleTank was alluding to.

 

[Alex_M]

Wonderful - thank you very much for your help. I'll check it out.

 

[Alex_M]

How are you checking for the dye leak? Eyesight only? With a UV light? Have you never noticed where a/c oil would leak out and leave a wet spot? Seepage at the compressor is hard to find sometimes and refrigerant is heavier than air. If you check at connections/seals areas, check at the bottom. Sure sounds like a leak at the evaporator, like @BattleTank was alluding to.

With UV. Negative, I have not noticed any AC oil. Thank you!

 

[BattleTank]

On another note.... Get yourself a new orifice tube, a can of a/c flush, new PAG oil and new freon. I can't believe they still sell that crap. You need to get that stop-leak out. Many a horror story about it. If you go to a shop and tell them you put it in, they won't touch it because it screws up the machines.

 

[Alex_M]

Understood and good to know - thank you.

 

[louu]

I never had any luck with dye. Go on Amazon and get a referigarant snifer/detector. Their cheap and actually work. Use it to sniff the compressor behind the clutch. Might new the condenser, the condenser on the 2016 and other years around that are known to wear and crack.

 

[z71wagon]

I recently ran into something similar with my 17 tahoe. A can of r1234yf(stupid expensive) would last a couple days tops. Texas summer is no joke this year so I was determined to find the leak. I ended up pulling the 90 degree elbow off the evaporator core drain tube on the firewall and stuck my sniffer in it, sure enough my sniffer went crazy. Not a job I plan to do myself, rig is going to the chevy dealer Monday, hopefully they find something other than what I'm thinking.

 

[73Vetteman]

I have been searching for an elusive leak for a year. A can of Freon would only last a coffee days. I have done AC work for 50 years but this one has me baffled.
GM decided to combine the AC condenser with the transmission cooler in the same unit. My Freon was leaking past the partition into the transmission fluid!
Replaced the condenser and problem solved.

 

[73Vetteman]

I have been searching for an elusive leak for a year. A can of Freon would only last a coffee days. I have done AC work for 50 years but this one has me baffled.
GM decided to combine the AC condenser with the transmission cooler in the same unit. My Freon was leaking past the partition into the transmission fluid!
Replaced the condenser and problem solved.

Meant to say “a can of Freon would only last a COUPLE of days”. Stupid autocorrect changed it!

 

[tooleyondeck]

+1 for evaporator, luckily on GMT800s the dash isn't too crazy to pull out. You can definitely DIY it if needed.

 

[z71wagon]

Update!! Gm confirmed my fear, evaporator leaking. Quoted me $5800 to replace!!! Anyone want a 17 tahoe with 122k miles on it, lol, no ac

 

[tooleyondeck]

Update!! Gm confirmed my fear, evaporator leaking. Quoted me $5800 to replace!!! Anyone want a 17 tahoe with 122k miles on it, lol, no ac

Sounds like you have quite the weekend ahead of you.

 

[z71wagon]

Sounds like you have quite the weekend ahead of you.

Yes indeed. Anyone else have experience with this. I like to think oem is the best replacement evaporator but mine didn't even last 125k miles. I don't want to have to do this job again.

 

[OR VietVet]

More Information for FOUR SEASONS 64064

More Information for GM GENUINE 1563894

 

[Alex_M]

Quick Q, somewhat related - how many blend doors are there? I've got the number three in my mind but cannot remember if that's correct. I've got an actuator that's been finnicky the last couple years, so I'm going to replace those while I'm in there as well. And finally put in that crack-free dash I've been saving.

 

[z71wagon]

Update, did the evaporator myself and only took a solid 10 hrs start to finish. And converted system to 134 instead of 1234. Ac blows way colder than before!!