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R12 to R134a A/C Conversion

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by blazer_87, Jun 20, 2004.

  1. blazer_87

    blazer_87 Registered Member

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    I am thinking about converting my AC from R12 to R134a, Looking for some advice. Anything special I should know before I attempt it? Thanks
     
  2. 4xcrazy

    4xcrazy 3/4 ton status

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    YEAH,,,,don't
     
  3. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    I am thinking about converting my AC from R12 to R134a, Looking for some advice. Anything special I should know before I attempt it? Thanks

    [/ QUOTE ]

    Well first even if they say you don't need to:
    Change the dryer, the orifice tube, and any orings you come across when you do this, and if your compressor is questionnable change it to newer compatible compressor. And blow through the system to clear all the old oil since the new one is different and you will ruin a compressor if they mix.
    And if you have a vacuum pump, vacuum the system and then introduce oil and gas.

    You want to do this once not multiple times.
    And know that the efficiency is lower with the R134.
    And you will have to replenish the gas every year since no hose can hold the fine particles the R134 are made of so they leak through the rubber.
    Even newer vehicles after a few years (2-3 years) will have that problem.

    /forums/images/graemlins/thumb.gif
     
  4. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I actually had good luck as far as the temp goes. I had mine down to about 49 degrees on a 90 degree day. Change the orifice tube, dryer, and O rings. Don't worry about the pump if you know it doesn't have a lot of hours on it. It will pump both R12 or 134, the pump doesn't care. The bad part about 134 is it expands and contracts much more than R12 so you can only hold 36 ounces of R134 in our systems(about 2.75 lbs) vs. 3.25 lbs of R12 that it holds.
     
  5. gm4x

    gm4x 1/2 ton status

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    Have your system evacuated (vacum pump) and refilled with Hot Shot. Don't blow anything through your system, it only adds impurities (moisture). Don't recharge without pulling a vacum on your system. Hot Shot is compatable as a "drop-in" for R-12, so system components don't need changed.
     
  6. 4xcrazy

    4xcrazy 3/4 ton status

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    [ QUOTE ]
    I had mine down to about 49 degrees on a 90 degree day.

    [/ QUOTE ]

    Hell, 90 degrees is cool out here !!! /forums/images/graemlins/yikes.gif

    I was told by an AC company i used to deliver to that another thing that i can change to help out with the cooling is to change the condensor to the new style used for the 134a freon, i guess the little thinkgy that make up the freon gas are a different size, and the 134 requires a better cooling condensor, although alot of people will say that they are large enough on our trucks, they actually are not. I have a '94 1/2 ton that came from the factory with 135, and the condensor is is different, not just in size, but the make-up of the tubes and fins, there are more of them.

    So basically i would say, do all that was previously mentioned, but also change out the condensor to a newer style i think they called it the serpentine style.


    BTW, HotShot will shorten the life of the seals, as it is a blended version of freon, with makes that the o-rings are not compatible with.
     
  7. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    I had mine down to about 49 degrees on a 90 degree day.

    [/ QUOTE ]

    Hell, 90 degrees is cool out here !!! /forums/images/graemlins/yikes.gif



    [/ QUOTE ] I didn't say it was hot but getting the air temp 40 degrees below the ambient temp is pretty darned good. /forums/images/graemlins/smile.gif
     
  8. 4xcrazy

    4xcrazy 3/4 ton status

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    I know, just givin ya grief, but yeah if it's around 90 outside here, i can get pretty good performance from my AC, but when the middle of summer hits, or heck, even recently it's only been hitting 104-106 outside, it only gets cool out on the freeway, then the engine heats up though,,,but i know why that is, but really when it's over 100 outside, and if i'm runnin around town, stop light to stoplight, it really sucks.

    Gonna replace my condensor and redo the system again real soon and see how it does.

    Will keep everyone posted when i finger things out. /forums/images/graemlins/thumb.gif
     
  9. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    [ QUOTE ]
    Have your system evacuated (vacum pump) and refilled with Hot Shot. Don't blow anything through your system, it only adds impurities (moisture). Don't recharge without pulling a vacum on your system. Hot Shot is compatable as a "drop-in" for R-12, so system components don't need changed.


    [/ QUOTE ]

    I sell this at work /forums/images/graemlins/waytogo.gif I run this ( shhhh....I topped off with it , never removed my 12 ..... ooops ).

    Ice cold today, last Tuesday , everyday /forums/images/graemlins/thumb.gif
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    I know, just givin ya grief, but yeah if it's around 90 outside here, i can get pretty good performance from my AC, but when the middle of summer hits, or heck, even recently it's only been hitting 104-106 outside, it only gets cool out on the freeway, then the engine heats up though,,,but i know why that is, but really when it's over 100 outside, and if i'm runnin around town, stop light to stoplight, it really sucks.

    Gonna replace my condensor and redo the system again real soon and see how it does.

    Will keep everyone posted when i finger things out. /forums/images/graemlins/thumb.gif

    [/ QUOTE ] Sounds like you aren't getting enough air through the condensor at slow speeds. /forums/images/graemlins/thinking.gif
     
  11. K5Chris

    K5Chris 1/2 ton status

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    i converted mine a couple weeks ago. works great. the evaporator coil and compressor should work fine with 134.... the condenser coil will work too, but, not nearly as good as a 134 condenser coil. if you wanna replace something, replace the condenser.
     
  12. azblazor

    azblazor 1/2 ton status Premium Member

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    I have converted 6 vehicles that I or family members own. They all work absolutely fine with R134A. I live in Arizona. Just do it right. Take the time and follow the directions if you use a kit. If a system is broke, fix it first, flush the evaporator, lines, and condensor. Replace the orfice tube or expansion valve, and the accumulator/dryer, replace the O-rings on all connections and either replace or have the compressor tested, use the proper oil and amount of oil, and make sure it pulls full vacuum for 1 hour and stays pretty much full vacumm for 15-30 minutes after the pump is turned off. Then recharge to 85% of the R12 amount called for, look for pressures to be 15% or so higher.
     

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