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A/C only works at speed, radiator fan works fine

Discussion in 'Gen 3 Prius Main Forum' started by Thenethiel, Aug 28, 2018.

  1. Thenethiel

    Thenethiel Junior Member

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    I've read through several threads on similar issues, but I haven't found anything that seems to actually be my problem. I have a 2012 Two with ~190k miles. The A/C only cools properly when the vehicle is at speed (30mph+ or so.) There is some very weak/intermittent cooling at idle. The radiator fan runs, sounds fine, moves air. The compressor runs because it does at least try to cool at idle and cools good on the highway. I've checked all fuses and charged the system (pure r-134a, nothing with additives). I think it may have a small leak but nothing that would cause what I'm experiencing.

    This was not a gradual change, this was a "working perfectly when I parked at the gas station, wasn't working when I started it again" change. So not even overnight, just being off for 5 minutes.

    Is there anything that could have broken just during a short stop like that that I can check, or am I screwed and need to take it to an A/C shop?
     
    #1 Thenethiel, Aug 28, 2018
  2. FuelMiser

    FuelMiser Senior Member

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    I'd say your "radiator" is clogged and only getting good airflow when the car is moving. Probably not an easy solution is to blow compressed air through the radiator in the opposite direction of normal airflow to blow out the debris lodged within...
     
    #2 FuelMiser, Aug 28, 2018
  3. Thenethiel

    Thenethiel Junior Member

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    Hmm I can try that, shouldn't hurt anyway. It seems weird that it would stop working so suddenly if that was the problem though.
     
    #3 Thenethiel, Aug 28, 2018
  4. Rebound

    Rebound Senior Member

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    Pretty sure that the air conditioner compressor on the Prius is electric. Perhaps you have the Prius ECO Mode selected?
     
    #4 Rebound, Aug 28, 2018
    Raytheeagle likes this.
  5. #1 Toyota salesman

    #1 Toyota salesman Member

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    Why do you think a leak in the system would cause that? If it's leaking and it has a certain threshold, for high pressure and low pressure. One second it will be above, the next minute, AT that threshold, the next minute, if it is leaking, it will be below that threshold.
    not saying that's the issue, just saying that it is possible for it to be working just fine one minute, and not working at all the next minute, because of a leak. Not to mention, a week, can lead to a bigger leak. I've seen a system just burst one day. That's how it happens. That being said, have you checked your pressure now?

    Posted via the PriusChat mobile app.
     
    #5 #1 Toyota salesman, Aug 28, 2018
  6. #1 Toyota salesman

    #1 Toyota salesman Member

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    BTW, low on refrigerant, would also cause it to get warm at idle, and cooler at speed, because the ambient air moving across the condenser, helps compensate for the higher pressure/loss of refrigerant.

    Posted via the PriusChat mobile app.
     
    #6 #1 Toyota salesman, Aug 28, 2018
  7. #1 Toyota salesman

    #1 Toyota salesman Member

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    What you need, is text stream, and you can actually look at the AC compressors are PMs , because it's a variable speed compressor. That will kind of tell you what it's doing in accordance with load of the system and speed of the vehicle. You also be able to see if it is cycling on and off, more than it should...which it would do, if it were low on refrigerant.

    Posted via the PriusChat mobile app.
     
    #7 #1 Toyota salesman, Aug 28, 2018
  8. Thenethiel

    Thenethiel Junior Member

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    It's not on ECO, it's not even cooling as much as it used when I did use ECO.

    Did you mean why don't I think a leak would cause that? Just because of how fast it changed, though your explanation of how it could makes sense. I'll be checking my pressure/trying to charge it again today when I get home from work. If it is indeed low again then it's definitely leaking and I'll have to get that fixed and see if that takes care of the issue. Unfortunately I don't have Techstream, but if it's leaking it's going to a shop anyway.
     
    #8 Thenethiel, Aug 29, 2018
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