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  1. #1
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    Default A/C system diagnosis?

    So I have this '89 STE which needs the A/C repaired.

    I'm not sure what happened to my gauges, I used to have some a long time ago. But I can get those.
    I've seen turbokitenc's posts and detailed videos.
    I guess I'm just not sure where to start.
    It doesn't look like it's been converted ever. I know the car sat from 2001 to 2015. As in, sat, and mabey very occasionally started, but probably not, I already cleaned the fuel system/injectors and got it running right again and replaced the tires from being permanently out of round.

    The compressor doesn't even try to cycle, never engages the clutch. Is that indicative of no charge or badd pressure switch?
    I don't mind replacing stuff but I hate to just replace a compressor without knowing if it's bad or not.

    I guess first I need to get some gauges and see if there's anything in there? If not, then what? Just do the dryer/fittings/origns and recharge with 152? If there by low chance happens to be fully charged, then where to look?

    I guess I just need steered in what direction I need to go first.
    Last edited by 73blazer; 05-30-2017 at 04:07 PM.

  2. #2
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    I ordered up some new gauges, new orfice tube, oil, duster, fittings, new dryer, oring kit and a valve kit, along with a couple little $2 tools like the orfice tube remover.

    If I hook the gauges up and there's nothing it in, I guess I proceed to clean up all the fittings, change the orings and dryer, and charge it up and see what happens.
    I kinda want to confirm the thing works first though, should there be power on one side of the pressure switch when I switch to AC mode , is that something I can check? I'm half tempted to just throw some r134a in it real quick and see what happens, if I can get the compressor to cycle, if it does, I'd remove it all, vacuum it out all clean, change the dryer/o-rings etc and fill it for real. But I think that's probably a bad idea.

  3. #3
    Senior Member turbokinetic's Avatar
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    If I were you; I'd think like this. Knowing you don't have gauges in-hand, I would start with physical and electrical checks.

    1 - With engine stopped, try to turn the compressor clutch hub by hand. A good used compressor will turn fairly easily, but will have a somewhat tight feel. There may be a tiny amount of backlash in it, but there should not be any notches or tight spots when you rotate it continuously in one direction.

    2 - There should be a low pressure cutout switch on the back of the compressor (assuming it has the V5 compressor). Disconnect this switch and tie a wire here that you can reach outside of the car. Connect your meter here. Start the engine and see if you get power here when the A/C switch is on. If you do get power here, then you can safely assume the system has lost its refrigerant gas charge and needs to be charged up.

    If the electrical and physical checks seem good, you'll need to get a set of gauges to go further.

    You may find that it will hold refrigerant for quite a long time without any significant repairs. They all seep slowly, and sitting for 14 years would definitely be long enough to lose the charge even on a good system.

    Hope this helps!

    EDIT: For some reason I didn't see your second message until after I posted this one. Sounds like you're on the right track. The electrical side of these A/C systems is very simple. Unless rodents damaged the wiring, there should be no reason for it not to work once charged.

    Don't forget that for the V5 compressor, you have to take the compressor off the car and remove the oil drain / fill bolt to pour out the old oil and replace it with new.
    Last edited by turbokinetic; 06-01-2017 at 04:48 PM.

  4. #4
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    I got some gauges today.
    I havn't tested the power at the low pressure switch yet, but the system was.....dead...zero, nataa, nothing. After seeing that I simply removed the schrader valve from the lower side.
    Zero contaminants. Super clean inside. I broke the dryer line free and that also looks very clean
    Damn I wish I had some R12, i'd be tempted to throw some in and see if it's workin. Oh well, at least it doesn't like like someone tried leak stop crap or over oiling it that I can tell so far.

    So my procedure is going to go somewhat like this:
    CHeck power at pressure switch
    ____-> yes -> check compressor for looseness/etc -> good -> remove lines/fittings/dryer ->
    _ __->no -> diag elec. problem ^ ______________-> bad -> replace ^
    __________________________________________________ __________________________>clean -> clean -> install lines/new orifice/dryer/fittings/orings -> vacuum overnight -> charge -> enjoy



    Look ok?
    Last edited by 73blazer; 06-03-2017 at 12:26 AM.

  5. #5
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    Yeah I got this all apart. System is looking super clean. No black death. Orfice tube was just very light oil film. Dryer was liquid free. Lines look clean save for perhaps a very very light residual oil film which I think is a good thing to find. I'll get the compressor out and clean/flush every thing up and vacuum and charge. If I'd had some r12 I probably could have just charged it and called it done.

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    The only oil that came out was in The bottom.of the evap coil. Nothing in the dryer. Nothing in the compressor. While it was a few ounces. It sure wasn't 8. . Not sure if that's good or bad.

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    I found the rest of the oil. It was in the condenser when I flush it out. It came out lots of it.
    I got the condenser and evaporator in the lines all clean and flushed everything looks super clean. I'm not quite sure what to do with this compressor. There was not a drop of oil in it, it seems fine. I think after years of sitting in non use. The oil somehow. Got left in the evaporator in the condenser. There was not a drop to be found in that compressor. Should I add a little bit then vacuum it down? I'm just debating where to add oil to or the most of it and most of its going to go into the accumulator, but I'm debating whether to add some to the compressor not.

    All in all the oil that came out looked clean. All the lines looked pretty clean and now they're bright super clean. The whole system looks pretty darn clean not like Turbokinetics Black Death videos.

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    I vacuumed the evap coil for 3hrs and the condenser for 3 hrs each by themselves. Each held 30hg perfectly after shutting down the pump for 15-20mins until I disconnected . So, I guess it's time to put this crap all back together and see if I get cold air??!?!?!?

  9. #9
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    The moment of truth isn't far away. Just letting it evac a while here. Everything's back together I put a little oil in the compressor and poured most of it into the new dryer ... New green or rings on every fitting screwed it all back together and everything nice and tight. It's holding 30hg of vacuum no problems. I did do one colossally stupid thing I was screwing the new conversion fitting on the high pressure port and twisted the whole fitting off the line. A lesson that tighter isn't always better... silly me. Luckily, the Schrader valve inside threads were still there and I was able to re-install a new Schrader valve and I'll just have to get some kind of a cap to go over that, but the Schrader valve is holding.





  10. #10
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    Well hot damn!. Or should I say cold damn. When I heard the compressor kick on after inserting the first can and starting it up and selecting max .....music to my ears. It's functioning perfectly. Quiet. Cold. I love it. My STE has a/c now. Blows around 44 out the vents. Holy crap. That's an involved project though. The better part of 2 days. But damn....compressor is super quiet I think it's gonna be just fine. It looked super clean Inside. No sign of shavings or nasty oil. Had I had some r12 I probably could have just charged it and been done.
    Thanks a million for your detailed videos Dave! They were invaluable here.
    Last edited by 73blazer; 06-04-2017 at 10:53 PM.

  11. #11
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    200mi trip to a customer site today in 82 degree weather. Blows cold! Not sure how accurate that gauge is but even if it read 5 low im happy.
    Giddy up!
    Last edited by 73blazer; 06-06-2017 at 03:48 AM.

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    It's 91 here today. Took her out for a drive and the hfc152a is working awesome. Blowing 45 out the center vent on a 91degree day...cant do much better than that. . Last week I took it down to a customer 200mi away on Monday and spent the week there and returned Friday afternoon. Worked awesome the whole time but temps were mostly in the high 70s at highest. . Today at 91 ... Seems to be holding charge after a week. . And the r152a is working great. The car is a joy to drive especially when your not sweating bullets.

  13. #13
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    Quote Originally Posted by 73blazer View Post
    It's 91 here today. Took her out for a drive and the hfc152a is working awesome. Blowing 45 out the center vent on a 91degree day...cant do much better than that. . Last week I took it down to a customer 200mi away on Monday and spent the week there and returned Friday afternoon. Worked awesome the whole time but temps were mostly in the high 70s at highest. . Today at 91 ... Seems to be holding charge after a week. . And the r152a is working great. The car is a joy to drive especially when your not sweating bullets.
    Awesome! Glad to hear it. I was confident that it would be a good repair.

    On the event that it leaks down..... there's an Office Depot in every town

    It seems that the R152A systems blow about the same temperature regardless of outdoor temp. That makes it seem to get colder to me, in hotter weather. It's more of a contrast to the outside temps.

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    That is so interesting how that works.

  15. #15
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    Well, she really got a workout today. Took the car out for a fathers day drive with my family down to see my dad, about 1hr away. 20mins in, fatality accident 1/2mi ahead (so we came to find out later). Everyone hard brake and.....parking lot. It's 82 out. Not terribly hot.....But we all know how a tarmac of 3 lanes of idling cars can become super heated quickly.
    Wait around for a bit (like we had a choice)....ah..yeah...nothing's moving..zero. Two cars overheated....another was missing it's driver (abandon), another 3 or 4 ran out of gas. 3 hrs later....cops show up are are trying to back people out of there one car at a time. Had we been 2 mins earlier or 15 mins later....there would have been zero delay or only slight delay respectively.
    But...being where we were....idle....A/C....(no pusher fan) ... still cold! Not as cold as if your movin' down the road at 70...but still cold enough. The car goes to 1k rpm if in park and A/C on...so I was in park..and blowing cold. But That pusher fan really would have helped! .... 3 hrs. That's hard on a cooling system, and an A/C system. Functioned perfectly!
    Didn't get to my dad's...but...I'm an optimist. I look at is as...I'm not the one who lost my life that day on that road. And I was comfortable while waiting the 3hrs to get off there.

    HFC152a......yeah baby!

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