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How do I convert R-12 AC system refrigerent to R134a?

jskhojskho Member Posts: 107
edited March 2014 in Mazda
1. When you release the R12, the hole in the ozone will get bigger. More people will get skin cancer... Any R12 needs to be captured and the work can only be done by a licensed technician.

2. R12 and R134a are not compatible. R134a requires a much higher pressure to work. Putting R134a in your A/C will likely damage your compressor.


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    0patience0patience Member Posts: 1,712
    Well, yes and no.
    Yes, the system is required to be recovered by a certified, not licensed technician.
    Yes, R-12 and R-134a are not compatible and yes they run at higher pressures.

    But no, it will not harm the compressor, as it is the same compressor used, but the condensor and some other parts will need to be changed out and the entire system thoroughly flushed and evacuated. The cheapy conversion kits usually end in catastrophe anda $1,000+ bill.

    Check my Profile for the AC experts.
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    swschradswschrad Member Posts: 2,171
    the refrigerant must be recovered, and needs to be unadulterated R12. also, all of the oil in the system needs to be purged, because it will gel in a R134a system. big fine if you get caught venting the gas yourself, and probable death of the compressor and valve damage if you put in R134a without properly blowing out the old oil.

    if it works, don't mess with it.

    if it doesn't, have it cut to R134a as part of the repair... a practical shop may refuse the work if you don't have the conversion done, even if equipped for full service of R12.
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    badgerfanbadgerfan Member Posts: 1,565
    I had the conversion done professionally on a '90 Taurus, also done when other AC work had to be done. Adder cost at the time for the conversion was not too bad. Kept the car another 3 years and the converted system worked just fine.
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    jskhojskho Member Posts: 107
    I just did that on my 93 626.
    Since you mentioned purging the remaining R12, I guess there could be no leak. If so, it may be a good idea to recharge when R12 is still available. On my car, I have it leak tested and they found nothing. They put in 1 pound and it now works fine. Since the 626/MX6 only takes slightly more than 1.5 pounds, recharging shouldn't cost a lot. I paid $70 per pound.
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    daysailerdaysailer Member Posts: 720
    is R-12!

    If you have a leaky system, it must be repaired in any case. Conversion is NOT a solution because the smaller molecule size and higher pressure will only exacerbate whatever leaks there may be. Once repaired and recharged, the R-12 system should not need attention for many years. R-134a is a significantly less effective working fluid than R-12 and it has a higher pressure vs temp characteristic which requires that a converted system be only partially refilled to maintain pressure within system capability. The result is diminished cooling capacity.
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    8u6hfd8u6hfd Member Posts: 1,391
    is I believe R606 (if I remember it correctly). It's cheaper and more compatible with R12 than R134a.

    It still contains small amounts of CFC's, but it is approved for the conversions.
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    daysailerdaysailer Member Posts: 720
    that are billed as "compatible", are MIXTURES the onstituents of which will leak at differnt rates and are therefore not stable over long term.
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    swschradswschrad Member Posts: 2,171
    DuPont's web site is quite cranky over the mixing of different refrigerant substitutes with R12... this is making it impossible to recycle R12 and will mean there ain't no more for fixing little normal gas leaks.

    I can see the point. I would not add R606, propane, or whatever is NOT R12 into an R12 system without a full purge and preparation cycle, and then only as a full charge.

    if you're going to do that, shoot, make the move to R134a and be done with it.

    lots of ways to put tape over a problem, often only one or two ways to fix it.
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    2k_impala_ls2k_impala_ls Member Posts: 311
    I retrofited my 91 s-10 blazer with 170k miles, myself. I bought the complete conversion kit for $24.99 that comes with everything you need. I followed the easy instructions and today in NY it is 93 degrees with 70% dew point and it cranks out the cold air. Don't listen to someone who never tried it before. Just make sure you dont have any leaks. Mine used to take 2 years for enough to leak out so it wouldn't work but I still had pressure in the system. The new kit comes with special oil to help the old seals.
    Believe me, it will work. I figured for $25 bucks even if it worked for a year I would be happy and it has been over a year. If alittle leaks out, just top it off. I even had some left over. Go do it and good luck.
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    mrdetailermrdetailer Member Posts: 1,118
    But the decision was easy since the air conditioner compressor broke and leaked all of the R-12 out. Put in new compressor and new hoses together with the R134A. Cost about $800 bucks 4 years ago. Probably because the compressor is new, it air conditions far better than my R-12 systems on my other vehicles. It is a positive delight in hot weather.

    If the R-12 system is still working without leaks, it has been cheaper to recharge every few years.
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    malachy72malachy72 Member Posts: 325
    and have had the same result. I had the certified technician evacuate the r-12 and I retro-ed the fittings with the kit. The r-134 gas is cheap and easy to recharge (I may have added some each spring) and the charging oil seemed to seal the o-rings. However, I don't know if we just got lucky, there seems to be a myriad of potential problems.
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