Diagnosing a/c problems
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This is a discussion on Diagnosing a/c problems within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I have a/c which worked... For about a week after I put some 134 in. Now I'm wondering why it's ...

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    Registered User poly_poly-man's Avatar
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    Diagnosing a/c problems

    I have a/c which worked... For about a week after I put some 134 in. Now I'm wondering why it's broken. I have suspicions based on previous posts here, and that I hear a hissing in about the glovebox area, that it might be the evap valve. Is there any way to positively or negatively diagnose this problem without the gauges? It'll be a while before I have access to gauges, and I'd like to figure out what the problem is now. Any other ideas about what problems it could be?

    Also, am I safe to throw at least part of a can in so that at least prom is comfortable? I'd hate to overcharge and ruin smth, but not sure how easily that happens.
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    Registered User dbya rx's Avatar
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    is the system still pressurized when the ac isnt working?
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    He simply abides. SD_GR's Avatar
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    If you have had to add 134, you had a leak.
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    Registered User poly_poly-man's Avatar
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    Quote Originally Posted by dbya rx View Post
    is the system still pressurized when the ac isnt working?
    Yes, which is the weird part - I'd expect with a leak that it would *eventually* go down to 0psig... after not touching the a/c for many months on end, it still had a bunch of pressure when I hit the schrader valve.

    When I added refrigerant the last time (the only time), the compressor kicked in almost instantly after I opened the valve - I put in the whole can (except for what was held in by pressure), but as I said - it kicked on almost immediately. After that, the compressor was cycling on and off, but it was full cold on the output , until that stopped working entirely. And again, I have a hissing sound from the glovebox area where all the magic happens.
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    He simply abides. SD_GR's Avatar
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    Get your hands on some gauges and see if you can at all avoid messing with the magic under the glovebox because if you do not have very small hands you may find yourself having to tear the car apart to get to a silly little valve.
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    Registered User poly_poly-man's Avatar
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    Quote Originally Posted by SD_GR View Post
    Get your hands on some gauges and see if you can at all avoid messing with the magic under the glovebox because if you do not have very small hands you may find yourself having to tear the car apart to get to a silly little valve.
    better certainly than paying someone $500 to do it! I'll get at some gauges, but for this weekend, I'll put in a can until the compressor cycles a bit less than it does in the very beginning. BTW, am I retarded, or do our cars not have a sight glass? That would really make things easier...
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    Quote Originally Posted by poly_poly-man View Post
    better certainly than paying someone $500 to do it! I'll get at some gauges, but for this weekend, I'll put in a can until the compressor cycles a bit less than it does in the very beginning. BTW, am I retarded, or do our cars not have a sight glass? That would really make things easier...
    Isn't there one on the suspension pillar? I don't recall. Anyway, look around because some refill kits come with a one-use rudimentary manometer. Get one of those because I hate adding stuff to a high pressure system without knowing the pressures.
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    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
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    Registered User poly_poly-man's Avatar
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    Quote Originally Posted by SD_GR View Post
    Isn't there one on the suspension pillar? I don't recall. Anyway, look around because some refill kits come with a one-use rudimentary manometer. Get one of those because I hate adding stuff to a high pressure system without knowing the pressures.
    People have done a lot worse without ill effect - I'm not even planning on throwing a full half a can in (and I already have the hose, so I don't want to spend 4 times as much on a can with the gauge).

    And I just took a look - there doesn't seem to be any part of the A/C system on the strut tower on either side - you'll have to show a diagram. My uncle a while back took a look and didn't initially with a cursory look see a sight glass...
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    He simply abides. SD_GR's Avatar
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    Two places to check: As you are facing the car, the US driver's side will be on YOUR right, or the car's left. Look on YOUR right, near the coolant overflow bottle, below and to the right of the bottle. There is a fitting there. Also look on the US driver's side strut tower, about midway up the tower (so roughly 20-30 cm below the top part of the tower).
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    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
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    Registered User poly_poly-man's Avatar
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    couldn't see the sight glass in either of those locations.

    Anyway, I picked up another 12oz bottle of refrigerant and a little 3oz bottle that has about an ounce of refrigerant, a bit of oil, a bit of leak stop, and most importantly, red dye (instead of the annoying uv stuff).I was about to throw a tiny bit of the regular refrigerant in, but I noticed that my compressor, when I started the a/c, at first went on for just a pulse and went off for about a half second, then the amount it went off dropped little by little, until eventually it just kicked on full time. I was getting slightly cooled air out the vents - not really working at all, but at least the compressor kicked on (probably a good sign).

    Anyway, I put the little can in, and I'll run with the A/C on all day tomorrow, even if it doesn't work, to get the dye circulated. I'll take a look for where it looks like my system is bleeding (although I didn't see anything initially). The one fitting that looks nasty (high side into the condenser), which I thought could be a potential leak wasn't even red, so that looks good. I'll try to put just enough refrigerant in to make the air work for tomorrow night (they decided to make prom 30 minutes away), without overcharging (by guessing, ofc).

    If I don't spot a giant red splotch, any ideas? Does everything still make sense to be a evap valve? If I don't spot a leak, I'll look into borrowing some gauges and other equipment.
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    He simply abides. SD_GR's Avatar
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    I'm betting leak; as to whether it looks like evap valve otherwise at most I can say "maybe" but my money's still on a leak.
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    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
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    Registered User poly_poly-man's Avatar
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    Quote Originally Posted by SD_GR View Post
    I'm betting leak; as to whether it looks like evap valve otherwise at most I can say "maybe" but my money's still on a leak.
    I'm seriously just hoping the leak's somewhere in the engine bay and not somewhere south of the firewall - I don't want to scrape red dye out of my carpet . I'd like it even less if I had to scrape red dye out of my gf's dress...

    and there's also a chance that the "leak stop" stuff works... although I'm always skeptical of that. If that's the case, does it make sense to have my system drained and refilled from scratch, just in case I've screwed up the balance of chemicals (i.e. so I don't overcharge by accident)?
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    He simply abides. SD_GR's Avatar
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    Consider the pressures involved and it may not seem very promising for the stop-leak stuff IMO. The engine bay is a likely place for a leak since the temps are more extreme, the environment harsher, and stuff moves around a lot too. My leak was in the engine bay.
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
    DISCLAIMER: Opinions expressed are the author's alone and are inherently worthless.

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    Registered User poly_poly-man's Avatar
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    hmm, after a somewhat-thorough glance through the engine (with about 1 hour of a/c running and 15 engine off), I see no red leak whatsoever - when the engine is a bit cooler and I have some more time, I'll run through very closely with a flashlight and look behind the glovebox and whatnot...

    ...but the interesting piece of data I can add is what happened when I topped off the refrigerant. Just now, I went to recharge the system, and to avoid overcharging, I had my mom tell me when the air got cold so I could stop. So, When I open the hood (a/c blasting, etc.), the compressor is spinning, there's still that constant hiss under the glovebox (hearable only in the car), but it's blowing hot air. I attach the hose, unscrew the top, and within one or two seconds, I hear the compressor make a somewhat disconcerting light clicking/tapping noise (clutch stayed engaged the whole time), and the air instantly dropped to ice-cold. I can't have emptied more than a few ounce into the system. I certainly hope it holds tonight!

    I don't know what that last bit means, but I'm under the impression that everything adds up to bad evap valve still? Any comments?
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    Registered User poly_poly-man's Avatar
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    ...hrm, I just noticed too that the evap valve hiss is actually cycling - it's off most of the time, but occasionally kicks on - in other words, it's probably not the valve.

    So... am I the one person ever for whom stop leak actually worked? I'll keep looking for bleeding a/c lines, but it's looking okay so far...
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

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