My a/c compressor failed about 2 months after I purchased my 2016 i3 Rex. This was July of this year - 2024 - year of the dragon. It was new to me, I didn't think twice about a bit of compressor noise when the a/c was blowing fantastically cold air. Eventually you could hear the compressor noticeable when charging the car - my concerns were alleviated by reading about how the a/c system works to cool the battery. But it got louder. And it got louder. And it was 100 degrees outside. And then one day there was no more wonderful cold air.
I got these codes:
Integrated automatic heating / air conditioning system
2 errors
801252: eKMV: internal component error
8013F6: Function test eKMV (OBD)
After a lot of crying, research, stress eating and alcohol consumption while researching, I decided to order a salvaged i3 compressor. This should have been a mistake, but my luck level is huge. You should just by a refurb. I would say buy a new OEM compressor from rockauto, but they have been out for a while now. They were selling them new at $900. I bought one on eBay described as pulled from a crashed car with front end damage. They warned that perhaps it had contamination from condersor damage. It was $150 so I bought it anyway. I have a gambling problem, as you already knew from my purchase of an 8 year old i3.
I also bought this overpriced compressor oil because it is the only one that exists that is actually safe for HV compressors. (the only one I could find - if you look at the Mahle data sheets, you'll find that many other oils people suggest are not approved due to conductivity):
A/C Compressor Oil (PAO 68 AA1 500Ml) - Mahle Behr 351214031
I also bought a cheap a/c flush bottle and 32 ounces of flush, which is way too expensive.
I had the a/c evacuated by some professional stranger that you should totally do legally.
You should also have a cheap set of compatible a/c guages and an a/c vacuum.
I removed the compressor, which is doable with regular socket wrenches, crescent wrenches, and a torx socket set if I remember all correctly. Also detach the a/c lines from where they enter the battery structure.
I removed the front passenger wheel, where you will find 3 a/c lines that run all the way from the back (low side, high side, and battery) to a connection block. If you detach these lines from the connection block, you can then backflush those lines. These were the only lines I flushed. I focused on the line that connects to the high pressure side of the compressor (the output). On my i3, there is what I assume is a filter on that line (thank goodness for that). I assume this because a LOT of metallic bits and pieces came out immediately when I flushed this line. The other lines did not have noticable chunks. This gave me hope that the destroyed compressor chunks with primarily stuck in that filter. I now think this, while saving the system over all is what led to the compressor failure. As this filter clogs from normal wear, the pressure is stuck more and more in the high side of the compressor, stressing it until it finally fails catastrophically. Perhaps flushing this line could have prevented the failure. I don't know, just a guess. To make sure these lines were dry of flush goo, I tooka shopvac to the back of the car and suctioned from that side of the lines for a few minutes each. Don't skip this. There was more crap in there.
I took the new compressor, drained whatever oil was in it, added expensive oil, sloshed it around, and drained that. I then added a very carefully measured bottom few lines of cheap plastic cup worth of the expensive oil (I saw this measurement technique in a Russian? compressor refurbishing youtube video). I installed the compressor. Reattached a/c lines, put a vacuum on the system, then attempted to charge with r134a. My 2016 specifies it on the sticker. The compressors used appear to be compatible with r134a and r1234xyz or whatever the new expensive gas is.
The compressor did not turn on. I cried some, and cleared codes, and cried some more when service light came back. Then I check codes and they were different:
Integrated automatic heating / air conditioning system
2 errors
801219: eKMV: Power reduction due to overtemperature converter
8013CF: eKMV: OBD HV voltage sensor above the valid range of values
This sounded different. This sounded like a power problem. Well, the compressors for this car have two major componets that you can easily take apart: the power block where the HV plugs in; and the compressor block where the a/c lines attach. It turns out you can unbolt the compressor, remove the power block without opening the refrigerant system, attach the old power block from your failed compressor, creating a frankenstein compressor from 2 different model years of the same compressor that failed, rebolt it, and try again.
I then turned the i3 on, and the compressor kicked on trying to suck freon, which was still attached from the previous attempt. I fed it approximately the rightish amount of r134a as indicated by a sticker somewhere, and the a/c has been perfect since. I live in daily fear of it failing again, have stress dreams about it, and carefully listen to every noise it makes everytime my wife drives away in it. But I feel like I accomplished something worth $4000 for about $300.
I took this slow with lots of breaks to think about what I was going to screw up, and it was probably two 8 hour days of work. To do this yourself, you should have some experience with charging a/c systems as you will likely be playing roulette with a $1000 compressor. You should probably also replace the condesor and expansion valves and stuff as indicated by the kits on ebay....but meh, that looked like way to much work.
If you need any clarification/pictures let me know and I will attempt to provide it.
The mechanic that look at the car is experianced with BMW I3, but not with the heatpump system itself.
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