So my 94 has a major leak that I or anyone cannot find. It leaks down in about 2 days. The backstory is I had a compressor clutch fail about a year ago so I replaced with an OE denso unit and drier. Evac and charged ran ok. Then I noticed a fain smell of refrigerant through vents and I put in red angel sealant. This worked for about 8 months sealing my evaporator. I would have changed earlier had I realized how easy it was. So a few weeks back all of a sudden it leaked out and ac quit working. So I ordered a new denso evaporator and drier and replaced. It leaked down in about 2 days. So I put my vacuum pump on it and it pulls great vacuum. I tested the system for leak by pulling vacuum for 30 minutes and shutting down the pump and it held for an hour. Charged it up again with dye this time just in case and it leaked out again after 2 days. So I combed over the entire system with blacklight and cannot find any leaks. So I decided the only two areas that could possibly be would be schraeder valves and or expansion valve connections. I pulled evap again and there was no sign of leakage, put in new orings again. Then changed the schraeder valves on all three access ports, vacuumed and recharged and again leaked down after 2 day. If I didn't have such fragile follicles I would be pulling my hair out. I am an auto tech with all the tools and have not encountered such a difficult leak to find before. Does anyone have any ideas where I can go from here? Any help would be greatly appreciated.
Impossible to leak nearly 2 lbs of refrigerant with dye and not show up.
Pull in garage and check all fittings with black light.
Make sure you check compressor too that is a notorious spot.
Mine leaks minor and I have to refill once per yr with 12oz can ($5 at Walmart). I changed the Expansion Valve, Drier and Condenser and used mineral oil on new O-rings.
yeah i hear ya. I have combed every spot with the black light in the dark. I put a 1/4 oz of uv dye in it. Shows up great in sight glass so I know it is in there good.
What's strange is it holds vacuum for an hour. I haven't tried testing it longer than that but with the gauges on it it doesn't budge. This is the way I've always verified an A/C repair. If the system was not sealing it shouldn't hold vacuum especially if the leak is large enough to leak out completely in 2 days. This is why I am completely lost here. I've done countless ac jobs and never ran into such a weird issue. It is leaked out now but not completely. It's not enough to cool but there is some refrigerant in the sight glass. The high side pressures are 80 and low side 20 now. i've gone over it with soapy water. I doubt it would be compressor as It sucks up refrigerant, holds ideal pressures and makes no noise. Plus the compressor is a year old and I rarely see a denso unit fail anyways. I replaced the original compressor only because the clutch failed and figured a whole new compressor would be a wise idea given the age.
I just wanted to update this thread in case it helps anyone. So I triple checked every oring, line , condenser etc. and still nothing. Then I decided to add some oil with the dye in it. I never added oil to the system since it came in the new compressor a year ago. Well added the oil and drove it for a day. Then I went to check it out and the compressor shaft seal is leaking and the clutch is saturated. That would be why no leak was being detected from vacuum test. I am just surprised that my compressor seal failed after one year since I rarely see Denso failures. So I ordered a new shaft seal kit and will pull apart and reseal this week since the compressor is functioning properly.
