Ac system advice anyone?

Discussion in 'Engine Performance + Maintenance' started by Tdean91491, May 15, 2020.

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  1. smdk2500

    smdk2500 I'm Awesome

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    Yes I know what vacuuming does. I do this type of work for a living except on systems that hold 20+ pounds of refrigerant and get way colder then the ac systems in our trucks. What i'm saying is i highly doubt that you got all the water out in a couple of hours. You might and you might not i'm not going to argue with you on it. Its you truck do what you want. I wouldn't take a chance of destroying a new compressor due to having used water to flush something when there is a product that works far superior and is designed for a specific purpose.
     
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  2. Erik the Awful

    Erik the Awful I'm Awesome

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    If you get it down to 28 in. Hg and it holds, your system is dry. Period. Water will not stay a liquid at 28 in. Hg.

    I, too, have worked on systems that hold more than 20 lbs of refrigerant. I also have a lot of experience at field-expedient maintenance. If you flush with water and then vacuum it down to 28 in. Hg. and it stays, you're fine.
     
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  3. Schurkey

    Schurkey I'm Awesome

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    At 28 in Hg, water boils at about 90 degrees F. If it's colder than that when you're doing the vacuuming, water would still be liquid.

    As long as the underhood temperature is higher than the boiling point, you'd be fine as long as the vacuum is held long enough to boil and remove the water.

    Professional-level AC vacuum pumps get mighty close to 30 in Hg. If you can get to a hundred microns, water boils at forty below zero.
     
  4. 1998crewcab

    1998crewcab OBS Enthusiast

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    41AMmBF+knL._AC_.jpg


    this is good stuff for o-rings and I use it on connectors for preventing galling of the threads
    worth the 9 dollars
    I show guys this stuff and how it works ...next thing they buy a bottle for A/C work
     
    Last edited: May 20, 2020
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  5. 1998crewcab

    1998crewcab OBS Enthusiast

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    # 5 is most important in my opinion
    " do not use PAG or ESTER oils for lubrication of the seal "
    this is also in the factory service manuals , do it right...

    Best article for general information on topic , a must read...
    hope It can help someone
     

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  6. Old Truck

    Old Truck Newbie

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    Have a 95 c3500 5.7, AC compressor seized up and won't turn, don't use the truck that often. Part was bought from Auto Zone with free replacement warranty. Would it be best to replace the entire system components, not knowing what crud is in the lines? I do not know if there is any freon in the system. I do not have a way to vacuum the lines. Any Thought?
     
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  7. Schurkey

    Schurkey I'm Awesome

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    Decide if you want A/C. If you do, have someone else do the work. You don't have the tools, knowledge, or experience to fix this successfully.

    AT MINIMUM, they're going to replace the compressor, the orifice tube 'n' screen, and the desiccant, (accumulator) plus flush the system. Replace the A/C oil. "I" would replace every O-ring in the entire assembly, and assure that the condenser didn't have folded fins, and the evaporator box wasn't plugged with leaves and mouse-nests. It would be a good idea to add an aftermarket filter on the suction side of the compressor. At that point, it gets vacuumed, leak-tested and only then refilled with refrigerant.
     
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  8. Old Truck

    Old Truck Newbie

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    Thanks for the feedback. That will have to be the third item on the truck's to do list. First is the front suspension (replacing everything except for the sway bar, 210k miles on originals), replace the dash pad (have had a replacement for about 5 or 6 years, just never got around to it. Blue is always a hard one to find that is in decent condition).
     
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  9. alpinecrick

    alpinecrick I'm Awesome

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    This^^^

    I use my airless and pump lacquer thinner through it. Then dry it out with compressed air. I do the same thing with trans coolers and lines, etc...
     
  10. Erin

    Erin Newbie

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    i have a 1994 k1500. I bought an AC Delco compressor from Rockauto 2 years ago. Pulley went bad on it after a year. Got the replacement under warranty and now that pulley is going bad. I did replace the required parts and flushed the system both times. What is a good, reliable brand to buy other than Delco?
     
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