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Thread: A/C compressor comes on but no cold air after recharge

  1. #1
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    A/C compressor comes on but no cold air after recharge

    My a/c has been blowing hot yet the compressor is coming on. I know from this forum that the compressor will come on if the R134 is low. I added a 18oz can and a 12oz can and it is still blowing hot. Why is it still blowing hot after all of this R134 I added and the compressor is still coming on?

  2. #2
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    It sounds like you're going to need the tool that tells you pressure differential between high and low sides. This will tell you if the compressor is operating correctly, and it will tell you if charge is correct.

    Also, the charge does not have to be off by much, even with an otherwise correctly operating system, in order to get results other than the one you want.
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  3. #3
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    Blindly adding freon without actually checking the operation of the system only works if it was working a short time before. Ie; you must have some reason to believe that a leak is the problem, and the system cannot be completely empty.

  4. #4
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    If you only added 30oz, that's still about only half full if the system was completely empty to start with.

  5. #5
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    Quote Originally Posted by Baupfhor View Post
    If you only added 30oz, that's still about only half full if the system was completely empty to start with.
    You cannot just fill an empty system though without vacuuming out the air/moisture and fixing what must be a fairly major leak.

  6. #6
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    Unless you have the knowledge and equipment to work on ac system, you are better off taking the car to a shop that specialize in ac repairs.

    Obviously you have a leak if the system if you can put 30 oz. of refrigerant into the system. Putting refrigerant into a system that is leaking out the refrigerant doesn't do you any good or the people that inhabit this planet or will inhabit this planets in the years to come.
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  7. #7
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    Does anyone know what the high and low pressure setting should be? I converted my R12 to R134. Would the settings be different? Does the system hold the same amount of freon if it was R12 or R134?

  8. #8
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    Quote Originally Posted by 70383roadrunner View Post
    Does anyone know what the high and low pressure setting should be? I converted my R12 to R134. Would the settings be different? Does the system hold the same amount of freon if it was R12 or R134?
    Would the settings be different? Yes

    Does the system hold the same amount of freon if it was R12 or R134 less for R134a.
    Quote Originally Posted by GarrettSR5 View Post
    Hate to admit it but attack_eagle is right.
    Quote Originally Posted by SpiritofBavaria View Post
    ............. then upallnight has probably got it right
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  9. #9
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    Quote Originally Posted by upallnight View Post
    Would the settings be different? Yes

    Does the system hold the same amount of freon if it was R12 or R134 less for R134a.
    I believe they are different.

  10. #10
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    Quote Originally Posted by Layne View Post
    You cannot just fill an empty system though without vacuuming out the air/moisture and fixing what must be a fairly major leak.
    Yes I know this, just saying it wouldn't be enough refridgerant anyways.

  11. #11
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    I have the exact problem. I am testing the pressures this week http://www.ackits.com/aacf/ptchart.cfm. I dont know if it is going to be the a/c compressor or system being clogged.

  12. #12
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    I took mine in after replcing the compressor to get the old school freon. I charged the A/C but no cold air. I was told there is a stuck valve somewhere in the interior of the car behind the glove box or something and its a real hassle

  13. #13
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    Quote Originally Posted by BMW IDFR View Post
    I took mine in after replcing the compressor to get the old school freon. I charged the A/C but no cold air. I was told there is a stuck valve somewhere in the interior of the car behind the glove box or something and its a real hassle
    Expansion valve, left of the glove box, on the right side of the heater box. Not too bad to replace. If you're equipped with a gauge set, a good vacuum pump and a hose crimper, theses systems are definitely DIYable.
    demet

  14. #14
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    Thanks for all the replies, I have a/c gauges and I test the system. The low side is incredible high and the low side is about 100.

  15. #15
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    If the compressor is turning on and off like it's supposed to, you've got pressure, and you're still getting heat, look into your heater control valves being stuck open.

  16. #16
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    Quote Originally Posted by lotusing View Post
    Thanks for all the replies, I have a/c gauges and I test the system. The low side is incredible high and the low side is about 100.
    Was the compressor engaged when you took the reading? Compressor has to be running in order for the low side pressure to be below the system pressure. With the compressor running, the low side pressure should be between 40 and 45 psi depending on the ambient temperature.
    Quote Originally Posted by GarrettSR5 View Post
    Hate to admit it but attack_eagle is right.
    Quote Originally Posted by SpiritofBavaria View Post
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  17. #17
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    Quote Originally Posted by Baupfhor View Post
    If you only added 30oz, that's still about only half full if the system was completely empty to start with.
    Man I think your way off, I dont know of a BMW that holds more than 2lbs of freon.

  18. #18
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    moroza is offline MORΩN ΛABIA BMW CCA Member
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    Quote Originally Posted by cirishmn View Post
    Man I think your way off, I dont know of a BMW that holds more than 2lbs of freon.
    Hi there, welcome to the forums! Before posting a reply, please check the last posting date to avoid...



    By the way, an early E34 535i takes 4.something pounds of R12. My 4/93 530iT took 3.42# of R134a.

  19. #19
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    The e34 holds over 3.00lbs ... great thread revival with incorrect knowledge though... hahahahaha
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