Prius 2011 A/C Overcharge Symptoms

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by bkydcmpr, Jul 24, 2022.

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  1. bkydcmpr

    bkydcmpr New Member

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    I have a new A/C compressor installed at a local workshop. It worked there but after got home I felt wasn't cold enough. During the day I went to a few places the A/C started blowing hot air, I heard the compressor keeps trying to start, goes on and off every a few seconds. The next morning, when I started the car, the A/C works again. After a couple of miles, A/C went back to the pulsing mode and stopped cooling.

    I found this video on YouTube
    shows exactly the same symptoms. It turned out the system is overcharged. Now everything makes sense, in the morning after the system cooled overnight, the A/C pressure got lower, the compressor started normally. After driving under the sun, the temperature raised so does the pressure in the A/C system, so it quits.

    I used a screwdriver to push down the the Low valve to release some coolant, until the system runs continuous (just a few pchits, really not much), everything is fine now.
     
    #1 bkydcmpr, Jul 24, 2022
  2. Tombukt2

    Tombukt2 Senior Member

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    Yes it's very easy to overcharge electric compressors.
     
    #2 Tombukt2, Jul 24, 2022
  3. JC91006

    JC91006 Senior Member

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    If the refrigerant amount is not correct (over or under charge), it would have problems. How did the technician charge it? There is usually a machine that puts in the correct weight. Also you should not be using "ECO" mode on your car if you want cold AC

    And hopefully the shop uses equipment specifically for electric AC compressors, the oil used has to be ND-11 oil and not regular PAG oil. Or you'll end up frying the compressor.
     
    #3 JC91006, Jul 24, 2022
  4. ChapmanF

    ChapmanF Senior Member

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    A/C shops have recovery equipment so they can solve that issue without releasing that stuff into the atmosphere.
     
    #4 ChapmanF, Jul 24, 2022
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  5. bkydcmpr

    bkydcmpr New Member

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    I watched the video at night, couldn't wait to find out if it would work. If a pchit made no difference I'd stop.
     
    #5 bkydcmpr, Jul 24, 2022
  6. bkydcmpr

    bkydcmpr New Member

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    The oil came with the compressor bought from carid. The shop used the machine to charge it. I don't think they have much experience with electric compressors so they didn't charge it precisely, as you could see in the video the compressor is very sensitive, just the coolant in the hose is enough screw it up.
     
    #6 bkydcmpr, Jul 24, 2022
  7. Grit

    Grit Senior Member

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    Oh the humanity!
     
    #7 Grit, Jul 24, 2022
  8. PriusCamper

    PriusCamper Senior Member

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    The shop thinks they're doing maintenance on standard AC, but truth is it's a variable pressure system and you have to measure refrigerant and lubricant by weight in an expensive machine, not by a pressure gauge.

    I'd head back to shop and force them to pay the cost of taking it to an auto AC specialist who has the correct equipment and complete the job.

    @lech auto air conditionin on Prius Chat has been incredibly helpful explaining all this to us over the years and one of his most recent posts outlines all the problems that happen when the AC system is incorrectly filled here: Oh dear! A/C blowing warm air - where's the cold? | PriusChat
     
    #8 PriusCamper, Jul 24, 2022
    lech auto air conditionin and bkydcmpr like this.
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