Milky sight glass after compressor replacement

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by MattFL, Nov 19, 2021.

  1. MattFL

    MattFL Member

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    The A/C compressor was recently replaced by the dealer a couple of months ago, and I just noticed today that the sight glass is milky white. It was clear before the compressor was replaced. The A/C is still working fine, but I'm concerned that it won't be for long. Can anyone tell me what would make it turn white like that?

    upload_2021-11-19_21-17-58.png
     
  2. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Check with dealership?

    Maybe two different kinds of oil used?? Seems like a "mayonaise" reaction, what you get when oil and water mix.

    saw something too, about “blown” desiccant bag.

    paging @lech auto air conditionin
     
    #2 Mendel Leisk, Nov 20, 2021
    Last edited: Nov 20, 2021
  3. MattFL

    MattFL Member

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    I'm not sure I trust the dealership at this point. Long story short, I took it in because the AC was warm. The service guy calls me back and starts going on and on about one of the pistons in the compressor went bad and there's metal everywhere. I know this is BS, it has a scroll compressor not a piston compressor, so I ask to talk to the actual mechanic. He tells me the compressor is bad. At this point I've got a wife who is not happy because her A/C doesn't work and a quote to make it work, so against my better judgement of getting a second opinion, I say go ahead and fix it. I got the car back and the A/C was working and I asked for the old compressor, which I received. Got it home, disassembled it and it was pristine inside, but at this point the A/C is working, the wife is happy so I go on with my life. Now FF a couple of months and when I go out to change the oil I noticed the sight glass, and that's where we're at today. So when I approach the dealership, I want to have more knowledge so I can call BS on the spot if they try to give me any more lies.
     
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  4. TMR-JWAP

    TMR-JWAP Senior Member

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    Does the sight glass look the same when the AC is on and off?
     
  5. gromittoo

    gromittoo Active Member

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    I am so glad to know that I have a sight glass again. When cars used R-12, they all had sight glass windows. When they used the more eco-friendly R-134 refrigerant, the sight glasses went away.

    Anyway, with a sight glass, you can tell a lot about the condition of the refrigerant inside. See if you can get someone to turn the AC on and off for you, while you monitor the sight glass. In the old R-12 days you would briefly see bubbles in the sight glass as the compressor kicked in, when the charge level was exactly right. If you knew what to look for, you would see streaks of oil at the same time. An experienced tech would be able to judge the amount of oil based on the appearance of those streaks. I don't know what refrigerant is used in the Prius (surely NOT R-12, since it is banned), but they put that sight glass there for a reason. R-412 is a replacement for R-12 that is less damaging to the Ozone layer.

    I do know that replacing a Compressor gets confusing about how much oil is in the system. The instructions for replacing a a R-134 compressor says to add oil, but how much oil is still in the system? It is not unusual that too much oil is added, which is almost as bad as not enough oil. Using the wrong oil is even worse (it can kill the compressor).

    I am going to guess that the dealer put in a full charge's worth of oil, while the rest of the system had about half a charges worth of oil. Now you have 1.5 times the amount of oil that you should have.

    Also: did they change the Receiver/Drier as part of the compressor replacement? They should have just to make sure there is no water in the system. Yes pulling a vacuum on the system gets most of the water out, but the "Drier" should still get replaced.
     
  6. ChapmanF

    ChapmanF Senior Member

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    If you've got a Gen 3, it's plain ol' R134a. And it has a sight glass.

    I had an old R12 ride with no sight glass. My R134a Prii have had the sight glass.

    I think it just depends more on whether the manufacturer bothers to put the sight glass in.
     
  7. gromittoo

    gromittoo Active Member

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    I guess you are right. My R-12 rides were all Hondas, which had sight glasses. My R134a rides were Cry-slurs, and I just assumed that the properties of 134a were different enough that a sight glass made no sense.

    Does this mean I could buy a Receiver/Drier with a sight glass for my 2001 Voyager van? I have never seen one for sale.
     
  8. MattFL

    MattFL Member

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    The sight glass is crystal clear after it sits for a few hours. The OEM oil is green, a bunch came out of the original compressor when I took it apart. Not like florescent dye green, but green/clear. Kind of like how motor oil is amber colored, except green.

    Here's a night-time picture with my phone flash, but the sight glass is clear like normal:
    upload_2021-11-22_21-12-49.png


    And here's what happens when you start it up:

     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Although I can't really make anything out in the second photo, if it goes from clear to not clear then you most likely have bubbles streaming through.

    ok, after a minute, it turned into a video and was a bit more clear. You can easily see the initial bubbles when the AC starts and then they appear to reduce to one bubble in the middle which then collapses, as expected. After that, it looks very odd, as you mentioned, turning an opaque color. Assuming it's not a ton of very fine bubbles, I haven't seen that previously. Are those very fine bubbles forming under the glass at the end of the video? With a good refrigerant charge, all my Gen 2s have stayed crystal clear. Without being there and seeing it first hand, I don't think I can provide worthwhile advice. I'll call this as being above my payscale.
     
    #9 TMR-JWAP, Nov 22, 2021
    Last edited: Nov 22, 2021
  10. MattFL

    MattFL Member

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    It's hard to describe, but it looks more like milk than tiny bubbles.
     
  11. Air_Boss

    Air_Boss Senior Member

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    Almost looks like some leak locating dye was left in the system.
     
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  12. gromittoo

    gromittoo Active Member

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    Leak Detection Dye is a real possibility. I have no experience with using leak dye on a system with a sight glass., but it makes sense.
     
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