bmw e32 750il AC LEAK

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Beamer.619
Posts: 1
Joined: Mon Nov 16, 2020 4:18 pm

bmw e32 750il AC LEAK

Postby Beamer.619 » Mon Nov 16, 2020 4:29 pm

Just some back story for the car. The ac was retrofitted from R12 to R-134a in 2000, the car had sat for about 15 years or so not being ran but within the last year ive got it running again i realized there was a no cold air in the ac system found out later that there was a leak on the compressor coming out from the bottom senor on the compressor. So I took the compressor out of the car replaced all the o-rings (that I had access to) and replaced the drier i also drained the compressor and refilled it with new oil. Then i flushed out the condenser while it was in the car because i could not figure out how to remove it. I then reassembled the compressor and then drier last. Next i pulled a vacuum on the system and did a leak test by turning off the vacuum while it was at negative 30 psi on the low pressure side using the high and low manifold gauges. The test showed that there is a leak because the negative pressure would not stay at 30 it was slowly going back to 0 psi indicating that there is a leak in the system. I then tried to find the leak with soap and water and could not find any leak so i pulled a vacuum for 2 hours on the system then I decided to try and charge the system with refrigerant to see if i could watch UV DYE leak out of the system to see where the leak was coming from. So i started filling the system with refrigerant into the lowside, it went up to around 40 psi before the compressor clutch kicked on. Right when the compressor kicked on the psi then showed a reading of 0 psi on the low side but the compressor kept running but it wouldn't let me put anymore refrigerant into the system it seemed. Also the air is still warm so it obviously isn't working does anyone see something i did wrong or know why this could be happening?
Dougflas
Posts: 350
Joined: Mon Apr 18, 2016 6:10 pm

Re: bmw e32 750il AC LEAK

Postby Dougflas » Mon Nov 16, 2020 4:44 pm

The system must not leak. Pulling a vacuum and using soap and bubbles will not work. Put some refrigerant in the system and use an electric sniffer to find the leak .I suspect you compressor shaft seal is bad/leaking due to the system not working for such a long time but this is only a guess. The reason why the low side drops to zero psi is probably because you are so low on refrigerant. Since you probably do not have a sniffer/detector, may be you can have a shop troubleshoott the system fo you and then make a repair yourself.

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