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A/C: low side very low, high side low too

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2 years 4 months ago - 2 years 4 months ago #61307 by adrian.c
A/C: low side very low, high side was created by adrian.c
I have an A/C question: my son who loves BMWs has acquired a 7 series that's seen better days (2011, 150Kmi) and the A/C is not working (we live in Phoenix so cabin cooling is about as critical as engine cooling).
Upon starting the A/C the compressor engages, the radiator fan starts running. The low side is very low, under 10psi, the high is 120psi, this was tonight when the ambient temperature was around 80F.
What would cause this kind of pressures and the best way to troubleshoot it further?

PS: revving up the engine didn't show any visible change in pressures.

thanks
adrian
Last edit: 2 years 4 months ago by adrian.c.

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2 years 4 months ago #61309 by Chad
Replied by Chad on topic A/C: low side very low, high side
Is it charged with the proper amount of refrigerant? I would evacuate and recharge with the proper amount of refrigerant, and re-evaluate.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."
I have learned more by being wrong, than I have by being right. :-)

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2 years 4 months ago #61312 by adrian.c
Replied by adrian.c on topic A/C: low side very low, high side low too
Chad, thank you for answering. I don't have any history, the static pressure is correct for the ambient temperature and equal between low and high, otherwise wouldn't know if the correct amount of refrigerant is in.

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2 years 4 months ago #61323 by Chad
Replied by Chad on topic A/C: low side very low, high side low too
Static pressure matching ambient temps is not conclusive. The ONLY way to how much refrigerant is in a system is to weigh it. I would recommend a proper evacuation and re-charge.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."
I have learned more by being wrong, than I have by being right. :-)
The following user(s) said Thank You: Tyler

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2 years 4 months ago #61328 by Cheryl
Replied by Cheryl on topic A/C: low side very low, high side low too
Sounds like an expansion valve problem usually when the low side is that low or even in a vacuum it’s a stuck expansion valve

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