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Recharging the A/C

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ozymandias, Jun 8, 2008.

  1. ozymandias

    ozymandias Junior Member

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    Our 2004 Prius's A/C has a leak. Rather than pay the 400-500 it would cost to fix it, I decided it would be cheaper just to recharge it once every summer. I tried recharging it for the first time today, but I came accross a problem. Even at 55psi on the gauge, I am still seeing bubbles in the sight glass. I'm a little worried since 55psi is in the "warning" section of the gauge.

    The bubbles are quite substantial...they fill up the whole sight glass and it looks "frothy". However, they come and go...sometimes it will be clear and sometimes it will be full of bubbles. So I have no idea what is going on.

    Does anyone know if the Prius runs abnormally high pressure in the A/C system?
     
  2. galaxee

    galaxee mostly benevolent

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    did you go to walmart and buy a can of refrigerant? if the answer is yes... bad news.

    the prius electric a/c compressor requires the use of nd-11 oil which is not electrically conductive. it is a dielectric oil. nd-8 or normal 134 oils are not dielectric.

    so basically it comes down to, cheap out now = pay big time later with a new a/c compressor. if you've already added the oil, which it sounds like you have, the system needs to be flushed out and hopefully no damage has been done to the compressor.

    unfortunately this is generally not a diy kind of job. i mean, technically you're supposed to be epa 609 certified to do refrigerant work in the first place.
     
  3. ozymandias

    ozymandias Junior Member

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    I bought a canister of pure r134a from the auto parts store. It's a can of Dupont, and there is no mention of any sealants or oils. I think you only have to be certified if you are doing work with freon?
     
  4. galaxee

    galaxee mostly benevolent

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    whew- you're in luck! there have been horror stories and we were afraid this was another.

    for the record, 609 covers any refrigerant work.

    so, where is it leaking and how much oil loss residue is there at the leak? we need to determine how much nd-11 you need to add to the system to get you through.
     
  5. ozymandias

    ozymandias Junior Member

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    Not really a matter of luck...more of a matter of doing my homework. I knew that I could only use pure r134a when I bought it. It's leaking at the high pressure line at the joint where the sight glass is. There is quite a bit of oil residue at the leak. If I have to pay $90 to get more oil I might as well get it repaired. My real question is, why am I still seeing bubbles at 55psi?
     
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  6. galaxee

    galaxee mostly benevolent

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    is the joint a welded joint or a bolted on hose connection? if it's a bolted on hose connection, you can replace the o-ring and they cost under $1.

    if you've lost a lot of oil, you don't want to run without it. that compressor needs lubrication.

    if there are bubbles, there's not enough refrigerant in there. about 100g of refrigerant is needed *after* the bubbles disappear. the repair manual indicates the quantity should be checked by weight rather than by the sight glass. here are the operating pressures
    Gauge reading:
    Low pressure side:
    0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm2)
    High pressure side:
    1.37 to 1.57 MPa (14 to 16 kgf/cm2)
    they don't give it in psi, of course.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The spec is 0.15 - 0.25 MPa (22 - 36 psi) on the low pressure side; and 1.37 - 1.57 MPa (199 - 228 psi) on the high pressure side.

    Is your pressure gauge reading 55 psi connected on the low pressure side?

    When you see the sight glass clear, this is probably because the compressor turned off or slowed down; I understand that the compressor is variable-speed.

    When recharging, do you have the cabin temp set to the lowest possible temp to force the system to work at full capacity?
     
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  8. ozymandias

    ozymandias Junior Member

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    Damn. I am reading 55 psi on the low pressure side. When I first hooked up the hose, it was 45 psi, before I added anything, and the bubbles were constant. I read on here that the 2005 models have an overpressure valve. Is that true for the 2004 as well?

    Yes, I have it on max cold with the fan on full blast.

    It looks like a welded connection. As far as the oil goes, it says in this post, that the compressor has an oil separator so there shouldn't be a huge loss in oil. Is that true?

    I am going to run out and take a couple pictures.

    I'm really confused now, it seems that the pressure is too high, but I am still seeing bubbles....what's going on?

    BTW, the A/C was noticeably cooler once I added the refrigerant. Maybe the gauge is off? Not likely though I guess.
     
  9. ozymandias

    ozymandias Junior Member

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    Here is the location of the leak. It looks like a lot of oil, but when I wiped it with my finger, it was actually pretty dry. The green color is from where the previous owner used leak detection dye (another no-no).

    [​IMG]
     
  10. patsparks

    patsparks An Aussie perspective

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    Stop being such a tight arse and go get it fixed properly.
    The oil would have mostly blown away in a mist so if you leave it unrepaired you will stuff the compressor, that will be real cheap to fix, not.

    That is saying nothing about the refrigerant you are spewing into the air.
    This isn't some junk yard get about car, surely it is worth looking after?
     
  11. ozymandias

    ozymandias Junior Member

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    Thanks for the helpful advice! Hey, maybe if it bothers you so much, you can give me some money to help pay for the fix? Otherwise, if you don't have any advice to give please go troll elsewhere.
     
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  12. GatorJZ

    GatorJZ Member

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    The point is it is horribly irresponsible to not fix refrigerant leaks. If you're not going to fix it, having the remaining refrigerant evacuated and recaptured..
     
  13. ozymandias

    ozymandias Junior Member

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    Hmm, well I wasn't aware that r134a was bad for the environment. I guess I'll look into seeing if I can get it fixed somewhere else. Like I said, the dealer wants $500. However, until I can get it fixed, that doesn't help my current situation.
     
  14. eclipse3g

    eclipse3g Junior Member

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    What you need to do is as follows:

    1.) Fix the leak

    2.) Pull a vacuum of 25+ inches on the system to evacuate all the air.
    (if you have gotten air in the system you'll never get rid of the bubbles).
    also this will tell you if you have fixed the leak, if its still leaking you won't
    be able to pull the necessary vacuum.

    3.) Add required oil to replace what was lost due to parts replaced at leak.

    4.) Charge the system with the proper amount of Toyota refrigerant.



    Sounds like you already have the gauge set, you will need a vacuum pump to evac the system.
     
  15. galaxee

    galaxee mostly benevolent

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    r134 isn't as bad as r12, but it still isn't good at all. hence technically needing the epa cert.

    you sure the leak isn't coming from that fitting above and not the welded joint? that's a fairly easy repair. do you have the glasses and uv light to detect the leak since the dye is already in there? spray the oil off with a solvent based cleaner, then run the a/c while looking with the uv light. will tell you for sure.

    refrigerant is a gas- it won't leave a residue. that is oil all over the place there. that oil lost needs to be replenished if you want your compressor to be properly lubricated.

    so if the pressure is high on the low side, that's a bad sign for your compressor- or the system is way overcharged. you can't get a particularly accurate measure of charge out of one of those cans, and the sight glass isn't worth much in telling you how much is in there. it's very hard to tell what's up here.
     
  16. ozymandias

    ozymandias Junior Member

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    Unfortunately I don't have a UV light to see where the leak is coming from. I am reading the gauge that is on the charging line...it's a proper gauge so I assume it's pretty accurate. However, if the pressure is high, I shouldn't be seeing any bubbles unless there is air in the line, correct? It sounds like I probably just need to take it to a shop and see if I can get it fixed for a more reasonable price.

    However, two of my questions are still unanswered. Does the 2004 have the same overpressure valve as the 2005? If so, the system can't be overcharged. Second, I read in another thread that the compressor has an oil separator so there shouldn't be too much oil in the lines themselves. Is there any truth to this? I look at the receipt from when the dealer topped it off last year, and they didn't put any oil in the system.

    Finally, the dealer said some special equipment is needed to evac and recapture the Prius's system. Is this true or just BS to scare me into getting it fixed at the dealer?
     
  17. patsparks

    patsparks An Aussie perspective

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    I am not trolling and as my advice has been backed up by several others (see posts 12, 14 and 15) I believe my advice was good advice.

    I am waiting for your apology.

    You local auto-electrician should be able to fix your AC, or a reputable mechanic with the required qualifications and certificates.
     
  18. ozymandias

    ozymandias Junior Member

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    I'm not going to apologize for someone who calls me a tight nice person and tells me to "just get it fixed" without offering any advice on how to do so. The posts you mentioned all provide some kind of information rather than just criticism. Furthermore, I am not the type of person who "just gets it fixed" without exploring all my options. I know a mechanic can fix it, but I have numerous questions about that avenue, as I have stated throughout this thread.

    There is no apology coming from me, and since it seems you clearly don't want to fully read my posts or answer any of my questions, you can move on to the next thread. I'm not going to wait around for it though.
     
  19. galaxee

    galaxee mostly benevolent

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    the overcharge valve isn't going to prevent you from charging 1 psi over spec pressure. it is possible to overcharge to a certain extent. and what if that valve doesn't work? just happened to someone we know.

    regardless of whether there is an oil separator (for which i'm not seeing any evidence), there is still oil in the lines. hence the oil stains on your a/c lines. the condenser up front will drip oil (literally, drops) if there's a big enough hole kicked in it. now there's not a ton of oil in the system as it is- even a little bit of loss is significant when you're talking a fairly small of an amount being there in the first place. the majority of the contents of those lines is indeed refrigerant. neglecting to properly lubricate the compressor is penny wise, pound foolish.

    no more special equipment needed for the prius than other vehicles- but you do need special equipment to recover, vacuum, remove moisture, and refill an a/c system on any vehicle.

    we do all our own work to our cars, but we just had to bring our camry to the dealer to have that vacuum/refill done. just yesterday, actually. if it was possible to do at home, we would have done it and saved the cash.
     
  20. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Can you measure the pressure on the high pressure side also? If the pressure on the high pressure side also exceeds spec, then it would appear the refrigerant is overcharged.

    If the pressure on the high pressure side is below spec while the low pressure side is above spec, then this would imply that your compressor is not exerting the necessary pressure in the system (perhaps damaged due to lack of oil from the leak?)

    The leak looks pretty bad, and I agree with the other posters that the sooner you can allocate funds to repair it, the better off the AC system will be.

    Good luck.