R134A retrofit Q's

Discussion in 'General Chevy & GM Tech Questions' started by User Name, Apr 20, 2009.

  1. User Name

    User Name New Member

    Just got a 93 sierra . 4.3L with 5 speed. Like the truck so far. But the AC doesnt work. The PO suggested recharging the system.

    Then I realized it was r-12. I would like to just recharge the system with r-12 and see how it works. But it could be compromised in some way.

    Please advise...and if you think a retrofit is in order.

    What all needs to be done for a retro...???
  2. KirkW

    KirkW Rockstar

    It's very difficult to buy R-12 nowadays (unless you're a licensed A/C tech, but even then it's expensive).

    I converted my sister's old '86 Chrysler Laser from R-12 to R-134a. I didn't notice much difference (technically, R-134a is less efficient). The kits nowadays contain the special oil and fittings to make the conversion happen.

    I have a 20-lb bottle of R-12 and the gauges, but I still wouldn't use it unless it was for a classic vehicle where originality counts. For everything else I use R-134a.

    The basic steps to convert the system are...

    1) Find (and fix) the leak
    2) Replace the accumulator (the dessicant inside to absorb moisture 'wears out' and should be replaced).
    3) Add the proper amount of R-134a oil (comes with the kit).
    4) Install the conversion fittings (also from the kit).
    5) Evacuate the system with a vacuum pump (very important step! If you don't get the air out, you can't fit all the refrigerant you need and it'll never be as cold as it should be).
    6) Add in the specified amount of refrigerant.

    If you don't have the parts and refrigerant, you might be better off contacting an A/C specialist and seeing how much they would charge to do the conversion.
  3. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    What Kirk said, but to add, you need to flush everything out of the system before adding the 134 oil. From what I understand, the 12 and 134 don't play well together. Wouldn't hurt to replace the orfice tube while you have it apart. Good luck

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