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Freeze-12 Vs R134a & New Vs Reman Compressor

Discussion in 'The Garage' started by mini_mull, May 1, 2007.

  1. mini_mull

    mini_mull 1/2 ton status

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    I did a little research but most of the threads on this subject are over 3 years old, so I think we could give it another go round.

    Anybody have any good/bad experiences with converting their R-12 systems with Freeze 12 or R134a. I know R134a is the standard, but I'm being tempted by Freeze 12's potentiel for lower temps and not being known for being as finicky as R134a. I have a very leaky compressor, and R12 is getting harder and harded to find, not to mention $$$. So which would you pick?

    Also wondering whether to go with a new or reman compressor. I've had bad experiences with remans in the past, some lasting barely past their two year warranty and some lasting onl weeks. However that was almost 7 years ago, so maybe they've improved?

    Shoot.

    Added:
    Doing a little more research and found another blend called Autofrost, if anyone's used that let me know.
     
    Last edited: May 1, 2007
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I tried a few blends over the last four years . Hell I even sell a r12 replacement at work ( need license to buy from me ) . And from what I found , is if you don't undercharge it , the head pressure shoots through the roof when its 110 degrees outside in AZ . I tried everything every technician told me , and what to look for on the gauges , had other guys charge it for me , and I kept blowing compressors or hoses .

    Been through two remans , and a set of old hoses .

    So needless to say , I bit the bullet and went r134a in my Blazer . It actually works fine , and I can get it at any parts store nationwide .

    The most important thing to do is keep the evaporator and the condensor clean .
     
  3. lectric80

    lectric80 3/4 ton status

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    I have been running 134a in my Astro for nearly three years. Two years ago I replaced the original compressor with a cheap reman from Napa. Never had a problem with it. Drove it to AZ in July and kept everyone cool. It is a black van as well but the AC blew ice cold even at idle, and nearly matched the factory R12 system that is in my 80 K5. Easily getting 32* at the vents on the Astro. When and if my K5's system fails I will replace it with a newer model AC compressor and serpentine setup, then convert to 134a.

    Just remember that r134a should be at about 80% IIRC of what the R12 was at. Make sure that the compressor hasn't put any particulates into the system, or you may destroy your new compressor.
     
  4. HammaK5

    HammaK5 Registered Member

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    I would go with a new compressor if funds are avaliable. For me freeze 12 has worked great. I used it in my 77 with a factory comp and lines only replaced the o rings, oriface tube, and dryer and it worked great. 134 does not cool as well at idle.
     
  5. Jason4x4

    Jason4x4 1/2 ton status

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    I would go with 134, and get a new condensor to go with it, the new style condensors will make the 134 blow colder. I have done a 134 retrofit on a 77 chevy truck, the only thing we added was a cooling fan in front of the condensor, we got the truck fogging over the back window it was so cold. Most blended refrigerant or replacements are flammable, I don't want to risk it.
     
  6. 4xcrazy

    4xcrazy 3/4 ton status

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    Ditto, i did this to the Burb, but then blew out a main o-ring on the back of the compressor body i believe,,,not the hoses or manifold head, so i figure the compressor it toast...

    anyways, if you compare the passes in the old r-12 condensors, with the new r-134a condensors, the 134 condensors have WAY more passes, with smaller tubes, allows for better cooling of the freon, keeps pressures down some, and makes for better cooling inside the truck.

    When i DID have the 134a working, with the old r-12 style condensor, it would definately get cold, but i had to keep the truck in motion(again, cooling & air flow), freeway driving and whatnot. The minute i started driving through town, stop light to stop light, and idling (did alot of this with my previous job) it would warm up and feel like a swamp cooler.

    Switched my condensors almost two years ago now:doah: need to pony up money for a new compressor, went all last summer without A/C...needless to say i just drove it to work and back, with a wet towel wrapped around my neck :D
     
  7. vortec

    vortec 1/2 ton status

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    true freon burns pretty well, too. r12 and 134a aren't nearly as bad as r22 (for buildings), though. hit r22 with an open flame and you'll get one hell of a headache, fast and better get out. one guy at my old job was soldering a pipe with his oxy-acetylene torch and he hadn't purged the line of freon (using nitrogen) like he was supposed to. the freon/acetylene mix makes one nasty gas when it burns and we found him passed.

    saturday, i gave my dad a hand on his oldest car, a 93 honda. it's an r12 system, and because the compressor is in a completely ridiculous spot bottom of engine on under about a million other things), we didn't even swap seals. we just used seal conditioner and kept our fingers crossed. no problem yet (in a whole 3 days. ha) and it cools great. for a seldom-driven vehicle, halfass works, sometimes.

    it's only been about 85 here, lately, but 95+ is just around the corner. i need to patch a screwdriver hole in my condensor coil (dang po) and do a 134a swap on mine, soon. texas summers show little mercy.
     
  8. BadBob

    BadBob 1/2 ton status

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    Another thing to get is the self adjusting orifice/valve thingy. Napa carries them, and they're dirt cheap. They make a big difference when you convert to 134.
     
  9. WhiteBurb

    WhiteBurb 1/2 ton status

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    I converted to 134 a few years back and now it leaks. I have to recharge it every summer. Haven't had a chance to trace the leak.
    I did go through one reman compressor. I'm pretty sure it was because I didn't do a good job of flushing the system after I replaced it.
     
  10. MaxPF

    MaxPF 1/2 ton status

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    Your question is sorta two-part, so I will answer it that way.

    In the stationary refrigeration sector the de-facto standards for "near drop-in" R-12 retrofit (meaning little or no modifications necessary to the system or oil) are MP39 (R-401A) and R-409A. Unfortunately neither are EPA SNAP approved for automotive use. This means it is illegal to use these in auto R-12 systems, even though MP39 and R-409A work VERY well - better than R-12 in many cases. Now, there is one refrigerant that is SNAP approved for auto air use that is very similar to MP39 and R-409A, and that is AutoFrost (R-406A). The only downside to any of these is that they contain a large percentage of R-22. R-22 will leak through nitrile o-rings, and it absolutely eats HNBR o-rings (the ones commonly sold for ALL auto AC apps, regardless of refrigerant). In order to keep it in your system, you need to use neoprene o-rings and seals (including in the compressor) and the hoses must be replaced with barrier type hoses (the standard hose for R-134A). Finally, the XH7 dessicant used in any accumulator you buy is incompatible with R-22. You need an accumulator with XH11 dessicant - good luck finding one. Freeze 12 is a blend of R-134A and another, higher BP refrigerant. It lowers head pressures, but it doesn't cool as well as R-134A, let alone R-12.

    The purpose of this diatribe is to point out that, unless you have a lot of time and money on your hands it is easier and cheaper to stay with R-12 OR convert to 134A. If done right, the R-134A conversion works as well as R-12, and is IMO the way to go if a compressor replacement is needed.

    Speaking of which, the R4 is a POS (this is in your 91 burb, right?). Your best bet is to replace it with a Seltec/Zexel/Valeo or Sanden compressor. See my thread to see how it's done:

    http://coloradok5.com/forums/showthread.php?t=193200

    Since you live here in the valley you can get the parts from Air Components in Mesa. I did the entire retrofit, all new parts except the evaporator (which typically doesn't need replacement unless its leaking) for $400. That includes refrigerant! If you don't have the ability to crimp hoses and pull a vacuum figure another $50-$100 for them to do it for you. $500 for a brand new AC system running R-134A that sports a super reliable and quiet compressor and will cool very well. That's a bargain IMO :deal:

    Finally, make sure your fan clutch is in good shape. Even new ones don't necessarily work very well - they won't engage until 220 degrees, which will make your head pressure shoot sky high and possibly vent refrigerant through the relief valve. Mine did this several times, and I finally jammed the thermostat spring on the clutch full CCW. It pulls tons of air all the time now, and my AC works great! Engine temps stay under 195 too :wink1:

    Edit: R4's don't lend themselves to rebuilding, which is why rebuilds are iffy. The new ones from CompressorWorks are junk. If you want a new compressor you are best off retrofitting to a Zexel/Seltec/Valeo (all the same) or Sanden. They are FAR better units than an R4, not to mention being quiet and using less HP.
     
  11. lectric80

    lectric80 3/4 ton status

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    That may be why mine worked so well. When I first tried to charge it with the 134a I found a leak in the condensor so I replaced it. The new one did have better/smaller passages that may have lead to the great cooling with the 134a. So that is something to consider when converting. I know that I changed nothing else originally, so the system was basically a stock R12, and it worked great. When I replaced the motor I replaced compressor, dryer, and orifice tube with an adjustable, but the van had already broken the condensor again so I replaced it again as well.
     
  12. mini_mull

    mini_mull 1/2 ton status

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    Thanks, guys for all your responses. I really could have made some costly mistakes without it. Well, it looks like the R134a wins. And I think I'll get a new compressor. I'm definitely interested in one that works better for less money... Max, have you tested how much colder you're running than ambient temps, now that it has warmed up?

    So here's my shopping list, tell me if I missed anything
    compressor (Zexel)
    condensor (for R134a)
    new orifice tube or self adj valve
    accumulator
    hoses?
    R134a- how much?
     
  13. MaxPF

    MaxPF 1/2 ton status

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    I have no idea. It gets plenty cold for me :D

    Your shopping list looks good to me. Th eonly other minor thing you will need is a male blade connector (crimp-on type) and some electrical tape. The clutch connection is single wire (the other end is grounded to the case) with a bullet-type connector on the end. You need to snip it off and crimp on the male blade. It will then plug into the hot side of the stock connector. The stock connector has a small diode across it - the side with the stripe is the hot side.

    Duh... I thought you were asking how much is would cost :doah: Uhh, I don't remember how much R-134A the system takes. About 60% of the R-12 charge is a good starting point - remember the condenser is different and will alter the volume capacity of the system. I charge mine by pressure & temp, but you need to be careful because it is easy to overcharge.
     
    Last edited: May 2, 2007
  14. lectric80

    lectric80 3/4 ton status

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    As far as amount of R134a, there should be a tag on your old compressor that shows the weight of R12 that was used in the sytem. My Astro used about 2.5 pounds originally, and I believe I am running about 1.9 pounds now. It should be about 75% to 80% of the original R12 weight.
     
  15. mini_mull

    mini_mull 1/2 ton status

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    Thanks, I appreciate it. I think I'm all set then, unless anyone has something else to add. I was hoping to do this myself, but I'm going out of town tomorrow and won't be back until Sat, so I'll probably have to have our mechanic do it. I'll talk to him tomorrow, give him all the info you gave me, and send him to Air Components. I'll think he'll be willing to trade labor, if not I'll wait till I get back, replace all the parts myself and just use him to pull vacuum and put in the R134a (oh, and to evacuate the old stuff because heaven forbid I cause global warming ;) ). Anyone know about how many hours a shop would normally charge for the labor involved?
     
  16. MaxPF

    MaxPF 1/2 ton status

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    Somebody needs to empty their PM inbox :rolleyes:

    I suppose I should mention that I do AC stuff on the side. :whistle:

    I'd be willing to coach you on the install if you want to do it yourself. It's actually a really easy install. The hoses are the only PITA if you don't have a suitable crimping tool.
     
  17. mini_mull

    mini_mull 1/2 ton status

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    Doh. :doah: Sorry, I'll take care of that right now. I'm always keeping to much junk, even in cyberspace. :wink1: Thanks again.
     
  18. mosesburb

    mosesburb For Rent Premium Member GMOTM Winner

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    I don't recommend a variable orifice tube. I sold many and every one of them came back. They are a great idea, but even the old timers couldn't get them to operate as advertised. Go with the stock replacement.

    Definitely new compressor. Might get lucky with a reman, but no a/c sucks, especially after dumping a bunch-o-money into a system.

    You should pick up some refrigeration oil. When you replace that many components in a system, you should add a bit here and there. I don't recall the exact amounts for each component (I always have to refer back to my factory service manual).

    I have done conversions from R12 to 134A and Freeze12. I like the Freeze12 better. 134A is definitely easier (practically buy 134A at Circle K), but I like the performance (pressures and cooling efficiency) of the Freeze12 better. That is the ONLY blend that I would use though. Some compressor manufacturers will not warranty their compressors if blends are used.

    Quantity of R134A will vary. I have never gone by a percentage of R12 charge to determine what amount of new refrigerant will be used. If you change to a modern condenser, they typically are more efficient, but have less volume, so total system capacity is reduced regardless of refrigerant used. I ALWAYS go by high side pressure and performance when charging (even R12 systems). With 134A t is usually a very sharp double edge sword. Adding a bit more might drop temps by a few degrees, but if high side pressure soars at idle, short component life should be expected. Sometimes (usually for me anyways) sacrifices must be made. Some system's performance is nearly identical to R12, but some just don't like anything else. A modern condeser usually helps quite a bit, but I would also add a condenser fan. I run condenser fans on all my vehicles (even my R12 systems) and they help a bunch--especially high side pressure at idle.
     
  19. lectric80

    lectric80 3/4 ton status

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    I use the percentage as a good base when buying the refrigerant, but use the high side pressure to determine what to add. The friend I had helping with mine recommended about 30 psi on the high side at idle. I know it climbs higher under throttle, but that definately gave a great cold air flow at the vents. I have never run a condensor fan, but will consider that on the K5 since I could use it to help cool the trans fluid in the cooler as well.
     
  20. 4xcrazy

    4xcrazy 3/4 ton status

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    30 PSI on the high side ?? :confused:
    my compressor, and my brothers didn't even kick on until the pressure on the high side was somewhere around the 50+ mark,,,30 sounds like a low side pressure to me..

    the systems i have worked on were working with system pressures at about 30-40 psi on the low side, and around the 120-130 on the high side.
     

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