If you SPA car has been diagnosed with the infamous evaporator leak or any leak in the system, get it fixed as soon as you can afford it, the longer you wait, the closer you get to full system replacement, which is astronomically more expensive than just the evaporator replacement. Also be careful who you get advice from, HAVC/MVAC space is crowded with hacks, who’s only solution is to “add freon”.
Back story:
I diagnosed a 2019 XC90 with the infamous front evaporator leak about a year ago, owner never end up getting it fixed because it’s an expensive job, I warned him the consequences of waiting too long, but he didn’t listen, instead some mechanic friend of him told him to just keep recharging it and it will be fine.
Anyway, the same car returned recently with the concern of AC not blowing cold at all after owner recharged it with 134a out of a can for the hundreds of time. After some diag, I got a sample of compressor oil and sure enough the compressor is burned out, aka black death. The delay have effectively turned the evaporator replacement into a full system replacement.
Pic for reference, pic taken from a professional MVAC group that I am in, not the actual problem from this car.
How did this happen?
Unfortunately, I don’t know for sure at this point, since the owner could not afford the full system replacement, I was not able to keep tearing down the vehicle to gather more clues, but I do have several theories, and I’m sure there are many other possibilities:
1. System was open to atmosphere at some point (all 134a leaked out), and owner recharged the system with 134a afterwards. Moisture and PAG oil mix together forms acid, and that ruins everything.
2. Compressor PAG oil leaks out with the refrigerant, and turn acidic when mixed with outside moisture, causing the leak on the evaporator to worsen overtime, similar to pic above, the corrosion on the aluminum TXV valve caused by a leak in the system due to failed O ring. When the owner recharge with 134A out of a can, it typcially does not come with any oil charge, and eventually enough compressor oil leaked out causing insufficient lubercation, which burned out the compressor.
3. Vehicle was operated extensively with incorrect amount of charge, causing compressor oil flow issue, which damaged the compressor.
Exactly what happened? We will probably never know, most likley it’s a combination of all of the above.