A/C and heat related questions

Discussion in 'OEM and Custom Interiors' started by 94SL, May 10, 2018.

  1. 94SL

    94SL OBS Enthusiast

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    My A/C is out, and I have a bad blend door actuator. I disconnected the blend door which stopped the clicking noise. Looking at the a/c system, my guess is the compressor (looks like the original Harrison R134 compressor) might of died due to an oil leak. Kind of dirty like maybe it sprayed oil and grime stuck to the oil. PO didn't feel like messing with it and unhooked the compressor. Luckily the PO unplugged it and tucked the wire + connector out of the way instead of cutting the connector or letting it dangle loose so it could get damaged.

    Anyhow, I have a blend door actuator on order, should be here tomorrow. The local parts stores (NAPA, AutoZone, O'Reillys) all have replacement compressors, rebuilds and brand new. AutoZone stocks a kit https://www.autozone.com/cooling-he...easons-kit-a-c-compressor/475877_157264_34477 that might be a better solution. I want to do this right the first time. Also don't want to do anything not needed.

    Guessing I should I flush the system? R/R drier? What about the condenser? orifice tube, accumulator? Tried doing a search because probably others have asked similar questions, but may have used the wrong words because I didn't find what I was looking for. A link to a write up is fine. A friend is a commercial/residential HVAC mechanic and has offered to help, loan tools, etc. I want to do it right and hopefully have it last several years.

    I am thinking I can repair the a/c without fixing the blend door right away with no issues, is this right? Guessing that the blend door just switches between inside and outside air intake. I will try to do this repair soon as possible, but if it proves troublesome to swap out as everyone says, maybe I can live with it as is for now. The a/c is a different matter. It was 103 degrees at 2 pm today so would really liked to get this done soon.

    ac compressor.jpg
     
  2. studigggs

    studigggs Newbie

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    Just went through this on my '90. Went through 2 compressors due to a dirty condenser (thought I could flush it) fouling the orifice tube. I'd suggest getting a new condenser (~$75) in addition to the dryer. HVAC tech should have you covered from flushing to leak checks and charging.
     
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  3. joep88cheyenne

    joep88cheyenne I'm Awesome

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    Also you may need to replace the dryer and or orifice tube just to warranty the compressor.
     
  4. 94SL

    94SL OBS Enthusiast

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    My friend came over, we plugged in the compressor, added some R134. Seemed to hold pressure. I started the truck and turned the air conditioner on. The compressor did not turn on. Measured voltage at the compressor wiring connector plug, and it was very low, less than 1 volt I think. I wonder if the connector is bad. Anyone know what the voltage should be? I may try and re-measure myself.
     
  5. magimerlin

    magimerlin I'm Awesome

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    From the top.....

    Did you put a vacuum on the system?

    Did you add the correct amount of oil to the system?

    How did you add some r134 with out the compressor or motor running and it "seem" to hold pressure? How much did you try to add this way?

    You can not add Freon with out pulling a vacuum first. You can not add Freon with out the motor running either.

    Do you have a set of manifold gauges?

    The compressor will only turn on when the system sees enough freon pressure, via the high side and low side sensors.

    Yes it should be more then 1 volt. Should be 12. If your testing at the connector and it's 1 volt have you tested further back? If it really is testing at 1 volt that's a voltage supply issue and most likely not a connector issue.



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  6. 94SL

    94SL OBS Enthusiast

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    Magimerlin

    Thanks for your questions. I will do the best I can to answer, but bear with me if I don't understand all that you say or ask. And not being knowledgeable on a/c systems, I might at times not accurately say what it is we did.

    On Thursday we did not put a vacuum on the system. Did not add any oil. My friend said we got a very minimal amount of R134 into the system. I'm just taking his word on that. The compressor did not run at all during all this. My guess is that our volt meter readings were bad. And I forgot to taking my own readings with my voltmeter.

    Today, we went over to my friend's shop. We did put a vacuum on it, of about 26.XX (not sure what the units are, PSI?) for a short time, probably 5 minutes. This reading didn't fluctuate that I could tell. We then were slowly able to get about 7 ounces of 134 into the system. The compressor cycled on and off frequently. It took a couple minutes per ounce of R134 installed, which my friend said was slower than it should be and said while it was good that the clutch seemed to work, it should not have been cycling off and on like that. Once we got to 7 ounces, the compressor stopped running. So, my guess is that the compressor clutch works, at least to an extent. Guessing the compressor is bad. FWIW, outside air temp was at 85, temperature at dash vent was 100 degrees.

    I asked my friend about oil, neither of us had any, he said there should still be some in the system, but #1, we were pretty much trying to see if we could get the compressor to run, #2 seeing if there were leaks. I guess #3 would be seeing if it would blow cool. Probably a half a$$ed way of doing it, but just trying to see what we have.

    I was busy yesterday and this morning and didn't see your comments until I got back from my friend's shop. Didn't ask him about redoing the voltage measurements at the compressor, but based on the compressor's working at all, cycling on and off, voltage is probably good since it was running?

    My friend is not too knowledgeable about automotive a/c, which he admits. He said he'll talk to some people he knows that have more experience on the subject and do some research. He and I were just trying to see if there was some simple fix to get it working. Starting to look like it might be more complicated than that.
     
  7. chipskittles

    chipskittles I'm Awesome

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    The cycling switch is basically a low pressure switch. They fail often in my experience. It's the one on the Accumulator(drier). It should have continuity with the vehicle off if the charge is reasonable. I would check the high pressure switch too, I believe this one is normally closed as well but I don't remember. You are trying to get your compressor to cycle on so you could always unplug the high pressure sensor it if it's stuck shorted, and replace it later.

    Compressor probably shipped with oil in it but you are normally supposed to adjust the oil level on installation to match what the old compressor had in it. I have rarely done this because very often the old compressor has no oil at all in it. It's much better to have a little too much oil than none at all.

    Replace the condenser, the R134 condensers clog easily and are impossible to flush effectively.
     
  8. 94SL

    94SL OBS Enthusiast

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    Thanks for the suggestions. My friend called me today and mentioned the low pressure switch. I will talk with him about the high pressure switch.

    I think I have read in the past that the accumulator and orifice tube collects all the garbage that is in the system and to plan on replacing them whenever there is a need to service the a/c. Or is it something else that needs to be replaced?
     
    Last edited: May 14, 2018
  9. 94SL

    94SL OBS Enthusiast

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    I had the day off today, so took my truck to a local place a coworker took his 74 Malibu for a/c service. They hooked it to their machine, pulled a vacuum, found a small couple leaks, fixed those, charged up my a/c and now its working pretty good. Since the PO had it unhooked for awhile, I was told there is a chance more leaks might develop as the system had likely dried out. So, get some use on it and bring it back if anything more problems develop. Price they charged me wasn't bad. Hopefully they got it solved and it will hold up for a couple years or more.
     
  10. 94SL

    94SL OBS Enthusiast

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    So, the a/c is still cooling pretty good. I have one of those 4 dollar harbor freight thermometers sticking in a vent and the temp at the vent drops pretty fast to around 50 degrees. https://www.harborfreight.com/hand-tools/thermometers/1-inch-pocket-thermometer-46586.html

    But, I'm guessing the a/c compressor may need replacing soon. The compressor started making a clicking noise today. It is definitely coming from the compressor, and stops with the a/c turned off. I am not surprised based on what the mechanic told me yesterday, but was hoping to get a year or more out of it with out having to tear into it.
     

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