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AC Diagnosis, attempt #2.

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  • AC Diagnosis, attempt #2.

    Poor AC performance. It works on the highway, but not too well in the city.
    High side: 360psi, low side: 32psi car: 1997 Acura Integra GSR

    My actions:
    1. ordered: expansion valve, receiver dryer, PAG 46 with die, R134A (2) Dupont 12oz cans, new O rings.
    2. Hired a garage evacuate the ac system.
    Installing the expansion valve allowed me to discover the evaporator was full of leaves and dirt (see pic), so it got cleaned too. New O rings, oiled with PAG.
    Quick vacuum test to make sure the expansion valve wasn't leaking, then onto the dryer.
    Added 1 oz of PAG to the new receiver dryer, new O rings, then vacuum tested again. Left the vacuum running overnight (10 hours). It held vacuum at -29 PSI over 1 hour.
    3. Recharged the system today - It drank 10.15 oz out of the first can, then 4.20 oz out of the second can... but I had to rev the engine a bit to get it in... that is only 14.35 oz in total, but the system should hold: 22.9 oz min - 24.7 max.

    Click image for larger version

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    High side: 360psi, low side: 53psi
    Today is 91F, 51%RH, expected pressures are: High side: 160-213psi, Low side: 32-47psi
    Blows warm air.

    Again the pressures are too high... little overcharged.
    Does the system have an extra 6 or 8 ounces of oil in it???
    I have owned this car since new... had a friend "top it off" years ago, he used a gauge set. I don't remember us adding oil.
    Is the condenser plugged???

    Since this is my first attempt at AC work, I would appreciate any help
    Attached Files

  • #2
    High side pressure (360 psi) indicates a condensing temp of 175 deg F which is too high. Given the state of the evaporator, what does the condenser look like?
    Try misting the condenser with a garden hose to see if the high side pressure comes down, and the low side becomes closer to 32 PSI.
    I have a condenser that looks real good until you look real close and realize the joint between the fin and tube had degraded and there was white powder (aluminum oxide) between the tube and fin reducing the heat transfer a lot.
    If you are not getting the heat out in the condenser it goes right back to the evaporator.
    Long and short take a hard look at the condenser.


    • #3
      Added pics of the driver side and passenger side of the condenser.

      Static pressure: 101psi (It has gotten a bit hotter here in Arkansas.)
      Started the AC: High side 230 psi, low side 30.
      As the car warms up, the pressures keep rising: High 315, Low 40 It is still rising, but I get the hose.
      Spray garden hose water on the condenser: High 170, Low 22.

      The JPEG compression make the pic look at lot worse. I don't see any oxidation at the welds, but the gravel road has dinged a lot of fins in the bottom 1/4 of the condenser.


      • #4
        It doesn't look bad, but the test doesn't lie, its not getting the heat out. The water spray gets the heat out and the pressures drop dramatically. 1st make sure the fan is working correctly and drawing enough air over the condenser. Air must be able to pass thru the condenser and radiator for cooling to take place.
        Start by cleaning and straightening the fins and make sure the fan or fan clutch is working properly.


        • #5
          So glad you are taking the time to help me. Thank you, Cornbinder89!
          So I checked the electric fans. The blurry one on the left is spinning.

          I grabbed my electrical meter, to see if the big fan is getting power. Only 2 leads on the electrical connector. 14.12 Volts. I doubt the fan has a temperature switch built into it... probably a dead fan.
          I should have started with this forum...it would have saved me a bunch of work. But I learned (the hard way), and I cleaned the leaves out of the evaporator that I never even knew were there, and I am less intimidated by AC work!

          Thanks again,


          • #6
            Sometimes the only to rule in or out on a condensers is to eliminate everything else 1st. Looks can be deceiving. The misting proved that if the heat was removed the system acted as expected, showed low, low side as would be expected with the amount of refrigerant you said you put in.
            So make sure the fans are operating as designed ( would agree that at 1st look, anyway you have one dead one, but a manual would be helpful to make sure), once you have enough air flow over the condenser see if you can get the correct amount of refrigerant in and see how it works.
            It would also fit with what you said on your 1st post about working at hiway speed but not in town.
            Last edited by Cornbinder89; 06-29-2018, 08:34 PM.


            • #7
              I got the fan motor off. Without the fan blade, it will turn a few revolution when I plug it in.... and it is squealing. So definitely a bad motor.
              My half full R134A can is still attached to my yellow gauge hose, and gauges. Will the puncture/hose attachment seal the can shut? I guess it can stay there for a week.
              The water test was a good learning idea for me. Thanks.


              • #8
                I've left a can on the tap for a coupla months 1/2 used and it still held, how much leaked? I have no idea. Screw the wheel all the way down to close off the line to manifold and it should hold for a week.


                • #9
                  Right on about condensers. Water is many times more heat exchange than air. Pics? It look pretty dirty to me at the bottom? Not sure just how debris or bugs? It's ok I can't be sure some pics are black X boxes in my view?

                  Can and taps: Some will hold for a year or more some wont when pierced. Pot luck the better the tap the better chance. There are brass ones with ACME caps for where the hose goes. Less than that type is less chance it will hold. Always some risk to lose all of it over a day or some hold indefinitely speak for my own. I write tare weight and if opened check that again later with a postal scale know what it did measures to single grams.

                  Side note is a constant always for A/C: Know your charge amount to the ounce if possible! When that info is lost you have to start over to known charge amount.

                  Squeaks with a fan motor. Don't try to fix those if so replace them. You said you would if not working totally as intended pressures and temps will be all off,

                  MetroWest, Boston


                  • #10
                    Thanks Tom. I ordered a new fan motor. Will update this in a week, once the part arrives.
                    The inline pictures were pretty small, but if I click on the attached picture, I get a full resolution picture.


                    • #11
                      See if this shows whole - your picture,

                      Back several you said you removed "leaves" from this. Is that how you left it or before? That's trashed with IDK what dusty crap so bad when it's supposed to drip water may have already clogged up the drain - hose or a slot just for that.

                      Pics? Oh my - a different thing with each device IDK but could click on that and it filled the whole screen got good view then. No matter what is not right or if it worked that needs cleaning up. Heater core should be behind that just the warning don't break anything if at all possible. Plastic stuff that holds all these things near always goes brittle any foam insulation should be able to replace if wrecked.

                      Try if still like that compressed air it looks dry and not sticky to me that might do? Never used one just see it is "computer duster" is a harmless way to get some compressed air no way to know how powerful if you don't have a lot out of a compressor for air and so on.

                      The ones that didn't show on my device not sure why? I'm using an HP, Win 10 laptop PC complete with it's own attitude may find out if it flies someday put it out of it's misery!

                      I'm not a picture guru some people have luck using sites like Photobucket or similar. I just use existing images off the web (images) they are already out there by the millions,
                      MetroWest, Boston


                      • #12
                        So I put a new fan in the front radiator, was able to get another 5.8 ounces of R134a into the system, bringing the total to 20.15 oz... give or take an ounce, as the can moves a bit on the scale as it empties, condensation builds up on the scale, the scale times out, causing me to remove the can, re-zero the scale, and set the can back down.
                        Should hold: 22.9 oz min - 24.7 max.
                        Pressures are: Low side 38 psi, high is 235.
                        If I bring the engine up to 2000 rpm, the low goes down to 22 psi, which is how I emptied the last can.
                        It blows cold air. Much better than before, but I wish it could be colder. It never did run real cold even when the car was new.
                        Should I buy another can of R134a and put more in the system? Or are the pressures good now? Today is 93F, 40% Humidity.

                        Click image for larger version

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                        Tom Greenleaf:
                        Your attached image is only a thumbnail, and clicking on it didn't bring up the big image. The leaves and debris in the evaporator have never been checked since the car was new (21 years ago), but I assume they got in thru the air intake (between the front window and the engine hood, I think). I vacuumed the evaporator, then washed it in the sink, with a bottle brush. It cleaned up nicely. Vacuumed the AC system overnight, because a few drops of water got into the evaporator during washing (even thou I capped off the ends, some got by.)


                        • #13
                          I'd want to put in another 6 oz about 1/2 a can. Your low side at speed is a little low, but that 6 oz may bring it up.
                          whoop's I mis read that I though it said 27.4 not 24.7 I'd still add a bit
                          Last edited by Cornbinder89; 07-10-2018, 08:22 PM.


                          • Cornbinder89
                            Cornbinder89 commented
                            Editing a comment
                            "Age enhanced" reading strikes again!

                        • #14

                          Tom Greenleaf:
                          Your attached image is only a thumbnail, and clicking on it didn't bring up the big image. The leaves and debris in the evaporator have never been checked since the car was new (21 years ago), but I assume they got in thru the air intake (between the front window and the engine hood, I think). I vacuumed the evaporator, then washed it in the sink, with a bottle brush. It cleaned up nicely. Vacuumed the AC system overnight, because a few drops of water got into the evaporator during washing (even thou I capped off the ends, some got by.)[/QUOTE]

                          >pic I just copy/pasted as it shows not enlarged by me. I can click on it with your format it expands to full page. That's each device I can't know what view anyone gets?<
                          OK so evap is clean but water got in IDK shouldn't matter under full well held vacuum should boil off. Trivia of it never tested is PAG oils do absorb moisture isn't good really don't know how fast - got me there. Brake fluid instantly it mixes water right into it!

                          The vacuum subject to debate. Some think you need to hold once full vacuum achieved seen by gauges that's enough of running the pump. If the same hours later great but hear of some leave them running for hours at best only solid ice would be the challenge.
                          Jury still out if the oil will give up moisture if it does mix in. I say no you would have to boil it out with heat or dump all of it totally flushed out.

                          The scale and small cans. Make sure shorter hose isn't throwing you off. Carefully check tare weights. It's different by brand of same product or tap and hose I know that just memory right now tare empty brass tap, hose and metal of can was about 6.6 oz doesn't matter what you have does exactly.

                          Know you can run the small cans thru gauges just set it up right. Assorted tools figure that out it's more accurate.

                          IMO - it's harder to tweak this system than some IMO by all observations at once and hit it spot on.

                          Smile Ross - you are newer than anything I own still! None needed cleaning evaps but could just not exposed to the dust/dirt whatever can get it I won't let them - my own stuff that is.

                          Two in use (my own) all original still lots of luck too do now leak out shaft seals with age figured after years of not finding leaks and good at that they don't like sub-zero weather if not running shaft and seal do not expand and contract close enough at age is why I'm about certain of that. Just one is exposed others are not don't leak kept at above 45F not used do bother to heat storage area if needed watch that remotely - never mind just the surprise leaks not found that's usually it if that happens where you are,

                          Last edited by Tom Greenleaf; 07-11-2018, 07:53 AM.
                          MetroWest, Boston


                          • #15
                            I managed to get another 3.7 ounces of r134a into the system, bringing my total to 23.85 ounces, which is within normal range for this car.
                            Pressures are: Low 39psi, high 270. It is 93F, 34% humidity... when the car is idling,
                            Pressures are: Low 25psi, high 295, when the car is at 2500 rpm.

                            The air is cool when we went for a test drive... My first time repairing an A/C system, and it worked! (Thanks to you guys, my secret weapon)
                            Thanks Cornbinder and Tom!