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Air conditioning problem

Discussion in 'Generation 1 Prius Discussion' started by SilverHCIC, Oct 13, 2010.

  1. SilverHCIC

    SilverHCIC Junior Member

    Joined:
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    Location:
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    Vehicle:
    2001 Prius
    Model:
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    The air conditioner in my 2001 Prius starts out blowing nice COLD air, but after about 45-minutes to an hour, it gradually gets warmer and warmer, until there is practically no cooling effect. This happens every day. Day after day. My evening commute home from work is about an hour, so the air conditioning starts out perfectly, but by the time I get home, it's just recirculating the cabin air.

    Since it starts out cooling the air just like when the car was new, I don't think I've lost any of the refrigerant. The fan works at all speeds. Plenty of air velocity out of the vents.

    Any ideas??
     
    #1 SilverHCIC, Oct 13, 2010
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Belt? When did you have the belt changed and tightened?

    Clutch failing? Can you see if if the AC clutch is opening?

    My recommendation is take it to a shop. They have the tools and technology to diagnose and fix the problem. My 'shade tree' exercises with the A/C have 'not been good' (tm).

    Bob Wilson
     
    #2 bwilson4web, Oct 13, 2010
  3. SilverHCIC

    SilverHCIC Junior Member

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    I'll check to see if the serpentine belt is loose/worn. I don't know how to check the AC clutch. What I can't understand is why the AC works perfectly at first, and gradually gets warmer after nearly 1-hour. ... It's been doing this every day for a couple months now.

    I would think that a problem with a belt or clutch would not follow such a consistent pattern. I know that when I hop in my car and drive home from work tonight, the AC will crank out COLD air right from the start, but after 45-minutes to an hour, the air will barely be cool at all.
     
    #3 SilverHCIC, Oct 13, 2010
  4. bbcb

    bbcb Junior Member

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    sounds like low freon causing the evaporator to freeze up.
     
    #4 bbcb, Oct 14, 2010
    usnavystgc likes this.
  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Thank you!
    I've seen evaporators jammed up with ice before but never thought to associate it with low freon. I always thought high humidity and the condensation not draining out before it got cold enough to freeze.

    I used Google and found this link:
    http://www.air-conditioning-and-refrigeration-guide.com/air-conditioning-freezing.html

    They mentioned low air-flow and that could be due to a dirty cabin filter located behind the glove compartment:
    [​IMG]
    In this photo, the glove box it out and I've run some ethernet wire from the engine compartment into the cabin. You can see the filter to the lower left. I simply drilled a hole in the plastic case and ran the wire through the hole to reach into the cabin.

    This is where the cabin air inlet is located:
    [​IMG]
    As you can see, there is a fairly large hole and others have reported finding leaves and rodent 'stuff'. To the right is one of the places where the VIN is imprinted on the body.

    FYI, I ran the cable to support some of my pre-OBD data measurements. I used a pickup coil to monitor AC voltage to and from MG1 and MG2 and later monitor a thermistor installed in the transaxle oil. Once I got my first Graham miniscanner, I haven't needed to make direct measurements but I've left the data cable to support future projects . . . and block the hole in the filter. <grins>

    Bob Wilson
     
    #5 bwilson4web, Oct 15, 2010
  6. SilverHCIC

    SilverHCIC Junior Member

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    Thank You !!!
    I'm not sure what is causing the freezing, but I think you are both right. That would certainly explain why the air conditioner works perfectly the next day ( ... well, at least for about an hour), and then slowly stops. Whatever is frozen is simply melting over night, and the system is able to function again (until it re-freezes). That seems to match my exact experience for everyday for the past several months.

    ... Now, to determine what is causing the freezing. Bob, the link you posted is quite thorough. It listed over a dozen things that could be causing the freezing. I guess the best bet is to sort them out in a logical order of likelihood, and investigate.

    I hope I'm lucky and I find it right away, and it's a cheap fix.
     
    #6 SilverHCIC, Oct 15, 2010
    1 person likes this.
  7. prius21

    prius21 New Member

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    Hi SilverHCIC,

    How do you do ?

    I just read that you have an ac proplem in your Prius 2001 and I almost have the same problem !!
    So have you found any soultion ?

    Even I took my car to Toyota dealer and the AC specialist doesn't know the exact problem :( :confused:

    Please let me know

    Thank
     
    #7 prius21, Jun 20, 2011
  8. rfaulds

    rfaulds New Member

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    Same issue.... starts okay, then lights blink... no cold air. The Toyota dealer/mechanics diagnosed the problem as the AC clutch failing and $500+ to fix the problem. As of now, we suffering with usually warm/hot air.
     
    #8 rfaulds, Aug 4, 2012
  9. ChapmanF

    ChapmanF Senior Member

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    You're in luck: your exact situation was thoroughly covered in this forum mere days ago.
    -Chap
     
    #9 ChapmanF, Aug 8, 2012
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