UV A/C Dye contamination

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by wendellroadside, Jul 1, 2026 at 2:41 PM.

  1. wendellroadside

    wendellroadside New Member

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    Hello i recently purchased a 2015 ct200 that had been in a fender bender and replaced the condenser, i rented a vacuum and guage set from autozone and attempted to fill the Freon. After about 15 minutes of slow filling I got the compressor to kick on and the high side started filling up faster to 95 which it then stopped filling, the low side pressure keep fluctuating down to 20 when I close the valve for the r134a can, but fills back up to 90 for a about 7 seconds when I open the valve, the low side is consistently fluctuating back and forth but the high pressure seems to be stuck at 95-100 range and I can not possibly get it to go higher than that after 2 hours of attempted filling. Compressor was engaged and running constantly. Low pressure line felt ice cold to the touch a couple times I checked but was not staying cold. A/C still blowing warm. After I took off the Low pressure coupler I noticed the Low pressure port is covered in U/V Dye, after reading online I have heard that this can cause compressor failure and needs a full flush and compressor, condenser, and drier replacement, I also read somewhere else that it just needs to be evacuated with vacuum again and filled this time with non contaminated. I am not sure what my next steps should be as there is not much discussion online of this topic. I am unsure if the A/C was operational before the crash but I believe it was. Any and all advice will be appreciated thank you.
     
    #1 wendellroadside, Jul 1, 2026 at 2:41 PM
  2. PriusCamper

    PriusCamper Senior Member

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    It'd be awesome if we could get lots of commenters on this thread from @Tombukt2 @ChapmanF @Mendel Leisk and others. We used to have lech auto air conditionin | PriusChat helping us at length but he's been gone for more than two years and we really need a thread about DIY AC that has some substance to it.

    I'm going to start reading through his old posts and posting some of his quotes here. Hopefully I can learn how to help you with your situation, which will help me as I'm likely soon to be in your situation.
     
    #2 PriusCamper, Jul 1, 2026 at 6:00 PM
  3. PriusCamper

    PriusCamper Senior Member

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    Also Prius is a variable pressure system so its done by weight, not pressure....

     
    #3 PriusCamper, Jul 1, 2026 at 6:06 PM
  4. ASRDogman

    ASRDogman Senior Member

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    That dye is horrible for any a/c system.
    The Prius a/c system is completely different than other system.

    And there are several articles/post about the a/c. Just gotta search. I know, it could be a pain.

    I seem to remember reading the best/proper way to fill the system is by weight, not by gauges.
    I don't remember how much, it might be on the sticker under the hood, but I'm not certain.

    I'll use 1lb as an example, 1 can, whatever it is.
    You can use a bucket of warm water to put the can in to force out the freon, or whatever you wish to call it.

    And it's very picky, 1 or 2 ounces too much or little, it won't work properly.

    Did you change the expansion valve also? And the receiver/dryer?

     
    #4 ASRDogman, Jul 1, 2026 at 6:55 PM
  5. Tombukt2

    Tombukt2 Senior Member

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    But you say it this 95 number or whatever we're talking about here you're making cold the fat silver line is cold that means the freon is getting pumped and it is doing its job. So when it stops making the cold something must be happening the compressor is now not running you should be able to feel and hear that thenyou need find out why on a 95° day you're looking for 37 or so on the low side pretty consistently and the high side is going to be in the 200s I do believe .
     
    #5 Tombukt2, Jul 1, 2026 at 8:26 PM
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