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  • bad expansion valve?

    Hello A/C experts! I'm new here and am hoping you guys can shed some light on an A/C issue in my poor mom's 2003 Honda Accord.
    Her A/C just recently stopped working. I rented some manifold gauges and am seeing 78psi on the low side/110psi on the high side, at 86 degrees ambient temp outside.
    The compressor clutch is not engaging and tapping on the clutch has no effect. The radiator/condenser fans operate fine.

    She had her A/C serviced back in 2013 and it has worked fine until a week ago. I reviewed her records from 2013 and saw that she brought the car twice to Pep Boys (yikes) in two months and they evacuated/recharged both times, and added a sealant both times. Then she brought the car back a third time a few weeks after, and they replaced a couple hoses and also the expansion valve and dryer. Like i said, it finally was fixed and worked well until a week or so ago.

    I'm not super happy that there could be sealant in the system. I don't want to influence a qualified diagnosis by mentioning my suspicions, since I am not an experienced A/C tech.
    I'd very much appreciate your input.
    Thanks!

  • #2
    Pressure should be equal if the system is static (no compressor operation) . With the two gauges not reading the same, the 1st question is which is correct if any?
    At 78 psi tells me the temp is around 80 deg. 110 psi it is around 93-94 degs.
    There is enough pressure that I would expect the compressor to turn on at least briefly, but with the gauges being questionable everything is up in the air.
    until the system is operating, diagnosis is pretty much impossible.
    I'd be looking for bad wire or switch to start with. With the condenser fans coming on, it tells me the dash control is calling for A/C but the signal is not making it all the way to the compressor.
    You are going to have to trace the circuit to find out where the power stops on its way to the compressor. It could be as simple as a bad low pressure cut-out or it could be a lot more involved.
    Where to go from here will depend on what knowledge you have, what books (information on the system) you can get and how good you are at it. It may be cheaper in the long run to have a real shop check it out.
    Until the refrigerant is moving in the system ( compressor running) you can asses any other components.

    Comment


    • #3
      Welcome.
      Sorry anyone used a sealer as you are not so thrilled either. There's no telling what it was or how it could have tried to work even the cans don't tell very well but you/we know it isn't a good thing.

      What to do now? I have a chart showing this system capacity is 19oz and should have from empty known only once can lose track 5.5oz of PAG-46 oil. Pretty much who knows now what's in it? Always stated use under-hood info first over charts if they differ.

      Onward? Pressures don't add up well for much to me essentially seems it's about empty of refrigerant. Hub on a clutch type compressor not engaged and two different pressure readings as YOU posted aren't right. That should just be "static" pressure about like taking tire pressure so your gauge probably isn't right or being used properly. There are different types how they attach what should be red hose and blue hose at manifold with knobs or how done there OFF is reading the High and Low. It those don't behave (rented set noted) guess you will need another set I can't believe those yet.

      How about if you wish rent (free in some places if you ask for 100% deposits) rent the vacuum pump and another set of gauges? The idea of a full vacuum that holds and a charge up to known weight is a diagnostic tool by itself. Not always so easy this is a low capacity system that is shut down.

      I have to say there's some IDK on my part what gets this compressor to engage if it's shut down like some others needs to be reset for a new grace period. AYOR at losing info most would respond disconnecting battery always best negative off first or only and on last touching a battery. AYOR if any other stored info, theft controls known to you and more can be lost know before do that or end up with a dead car totally possible!

      They sell pure 134a in 18oz cans says just 134a not junk in with it. Yes, a can with a gauge used on low side only feared by me and most. That's close enough to 19oz to work. Trouble is getting all of that in without compressor? You wont. Maybe 1/2 into a vacuum with can put in warm water and shaking it??

      What I'd really like is to find the leak first that's still the #1 reason for A/C to not work and stay off/disengaged.

      It's that or pay for leak finding only now then decide what you wish to do. I like electronic leak detectors (sniffers) are fussy, very costly and you wont rent one that I know of and too costly for a one time use - you may think otherwise.

      Sorry I'm still trying to pluck out a reasonable plan for you.

      Yes - Just pay to find the leak now. Do add dye that should already be in it if not on a vehicle that was worked on before just dismayed. Oil evidence alone is a clue or even bubble tests back to like a tire use plumber's leak finder just lasts a little longer before drying out than soapy water.

      Long reply - sorry: Most common is a shaft seal of compressor, evaporator with damage up front and or any connections. Still can be high on the list is the service ports themselves - do not neglect checking those will bubble for a little once but shouldn't twice just with caps off.

      Bummer about the sealer is messing me up I don't want to suggest wasting huge bucks if a disaster you and your Mom may not want to go that far?

      Your call info can't be right from those gauges,
      Tom
      MetroWest, Boston

      Comment


      • #4
        Most shops will not work on a system that has had sealer added.

        Agree that the compressor clutch must engage for any real diagnosis to begin.

        Comment


        • #5
          Quote colin's post: ">78psi on the low side<" Stuck on that if compressor off. That's below temp and other was above. I don't think it read properly so guessed. Seems sure with a tap test is isn't getting power to engage then the list of reasons why not it should be enough if even close. I just can't know if this shuts down if a pressure has stayed out of ranges so it has a chance not to disable the vehicle?

          Sealer is the choking point - twice. So true Cusser I wouldn't want my stuff touching it knowing that but might waste some death kit gauge for a static maybe pressure. I've never seen the stuff work and last if it did leaks would never be the problem again. Another guess it's leaking again so find it hopefully by evidence of some yuk somewhere it could flow at a connection, seal or condenser. Back to if not stop and send this out if only diagnosis already said that,
          Tom
          MetroWest, Boston

          Comment


          • #6
            Thanks guys! I think I will try to rent a different set of gauges, to rule out faulty equipment. I'll test the clutch wire for voltage to see if it sees 12v. I might even try to send 12v directly from the battery to see if the clutch engages. Finally, i can see if any dye is visible under UV, since I believe some was added in the past.

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