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R134a vs R12

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 85K5inGeorgia, Aug 1, 2002.

  1. 85K5inGeorgia

    85K5inGeorgia Registered Member

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    I wanted to run this by some of you. I have a friend that told me he put R134a in his R12 system in a domestic auto 4 or 5 years ago. He said that it works fine without going through the conversion. Anyone heard of this or know anything about it?
     
  2. 76chevy

    76chevy 1/2 ton status

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    Someone here mentioned doing the same thing but I don't remember who it was. It was in a post about AC stuff you may want to do a search and see what comes up.
     
  3. shane74

    shane74 1/2 ton status

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    I did about a year ago in my wife's buick. It's a 91 with a 3800 V6. Total price was about $100 for the kit and the replacement parts I needed. It has worked great ever since. But.....you need to evacuate/flush the system thoroughly, and fix what ever casued it to go bad in the first place. Some say that the freon loses its charge. It doesn't. The only time your AC should quit working is when you have a leak and/or other mechanical problem.
     
  4. Skroo

    Skroo 1/2 ton status

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    To properly convert a system you need to replace the accumulator or reciever/drier and all of the O rings. Then drain all of the old oil and flush it. There is a different oil for 134 and R-12 and they won't mix. 134a oil will eat R-12 seals. You also can't put the same amout of 134-A in the system becouse it runs at a higher pressure, it something like 80% (I think) of what you would put of R-12.
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Its not that hard to be honest. We got all the stuff up at our shop to do it and I spent a day with a pro and he showed me the ropes. All we did was evacuate it (put it on a vacuum pump) and fill it with the new stuff. I used three cans of the r-134a with some additive called maxi-cool in it. I bought it at advance autoparts. I was really more interested in the oil in it. The GM R4 compressor needs about only 6 ounces of oil. Three of the big cans will give a pinch over 2 lbs and 6 ounces of oil, perfect. Most of that conversion oil uses what is known as Polyol Ester oil, its R-12 mineral oil friendly. If its feasible, you can also take the compressor off and turn it over a few times and hold it upside down to get some of the old oil out. It doesn't hurt a thing, doesn't contribute though either, it just finds a low spot and sits. PAG oils shouldn't be mixed with R-12 mineral oils and thats where most of the problems you hear about. Every A/C system leaks, no matter how good. I guess the deal is that it will leak through the hoses (we're talking very very small). It make many years to lose enough for a recharge. I guess their working on leak proof hoses, along with electric compressors, and an A/C system that works on CO2 and has operate in PSI range of thousands. Crazy stuff we'll have in our flying cars in the future, haha.

    Put a vacuum on it and go get a beer and see if it holds. Then put a little charge in it to get the compressor to engage and check for anything odd. I had a leak on the back of my compressor and a load belt squeal when we discovered the compressor was siezed. A/C work is so damn easy, its almost pathetic. That is unless you have to go digging through hell to change condensors or changing hoses placed in insaine spots.
     

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