Shocker, another post about a mini excavators A/C not working.... ha Anyway, 2015 Cat 305E2. H5M01334 A/C works great when its charged, but never holds a charge very long, a few days, up to a week. I charged the system with nitrogen up to 150psi, as thats all I had left in my tank. Over the course of an hour, it dropped about 5psi. Same with vacuum, it'll get to about 28 inches, then slowly creep back to zero which means there is a leak FOR SURE somewhere, not just a stupid rolled O-ring that will seal up under just vacuum, or just pressure. Before testing it today, I put the gauges on it, and it had about 3-5PSI in the system, MAX. So, it will leak completely out, not just down a little. I've sprayed ALL of the connections I could find or access, including the condenser with soapy water. I've used a sniffer everywhere I could get it after charging. I even had the sniffer stuck down by the A/C compressor and not even a hint of a hit. Doesn't need to be running to lose charge, so I feel the compressor seals aren't the culprit. HOWEVER, back when I got this machine, the A/C Evaporator was CAKED with dirt. So, I cleaned it off, and this was the end result, see the before and after photos below. It also had that dark area, which I assume is likely pag oil. What are the chances that this evaporator has a pinhole from all the dirt caked on it and rotting the evap? I feel like that I can smell the freon when I first use it during the day with the fan on. Then it dissipates. The A/C refrigerant and oil has that distinctive smell. I don't want to rip the HVAC box back open to spray it with soapy water since its kind of a pain to get into just to close it back up to wait for parts to come in, but everything I keep finding points here. If the consensus says this is likely my culprit, I will replace it and the drier unit. Just sucks because that evaporator is $848.61 (453-8582) and the drier unit is $47.73 (415-5056), and I should probably replace the expansion valve (306-5618) since it's right there by the evaporator, and its another $91.13. So, this is an easy thousand dollar endeavor. I am fully capable of doing this properly, but I don't want to throw money away either. So, at this point, should I just replace the compressor too? lol (422-6493), for another $416.13. It would be nice to find all of this stuff a little cheaper, but I have ZERO pull for that. It also sucks, that replacing the compressor requires moving all of the cooling radiators out of the way, unless someone has better ideas... Anyway, thanks for reading, if anyone has any extra insight, or thinks I am on the right or wrong track, I'd appreciate the feedback.
you can use uv dye. Then use the black light and find the leak. If it’s that fast, should be easy to find.
add refrigerant with leak detecting dye. Usually comes with a little black light, if not get one too. Check for leaks in the evening, it’ll be readily obvious. Certified A/C Pro R-134a Leak Detector UV Dye 1.7oz Shop for Certified A/C Pro R-134a Leak Detector UV Dye 1.7oz with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store. www.autozone.com
If it was my machine, bear in mind I am a cheap bassard, I would try a can of 134a stop leak and then fill with 134a and run it for at least one hour to see if it helps. I have used this in vehicles/machines that had a very slow leak and they are still making cold air. Those that do not believe in stop leak will get a very good laugh out of this.
Stop leak works, but causes more problems down the road, so I wont use it. I haven't used the UV Dye setup yet, but I might give it a go. I've got a feeling I am going to run into the same thing though, not going to find anything and I am going to have to open up the heater box to find out thats where its leaking.
Your evaporator is rotted and that’s where you will find the leak.
In the photos the evaporator appears to be so corroded it probably requires replacement either way. Replace it and see what happens from there.?
That’s kinda what I was thinking. Wish people would shut doors when they turn the AC on….