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Propane as R-12 Replacement?

Discussion in 'The Hokey Ass Message Board' started by El Caballo, Jan 9, 2014.

  1. El Caballo
    Joined: Mar 3, 2001
    Posts: 5,913

    El Caballo

    I read on a Cadillac forum that some guy replaced his R-12 gas with propane and it was still working after a year. Any A/C experts here care to verify or debunk this?
  2. Danny G
    Joined: Aug 1, 2006
    Posts: 399

    Danny G

    I worked in a refinery and propane was used in most cooling services
  3. fsae0607
    Joined: Apr 3, 2012
    Posts: 871


    It'll work, but very dangerous in a crash and if a line ruptures! :eek:
  4. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856


    My buddy is an AC/Refrigeration guy (as well as a car guy) and he says propane will work as an R22 substitute-- R22 is different from R12 and is used in low-medium pressure systems in refrigeration and central air conditioning.

    Different systems are designed for different refrigerants. He says propane will probably function to cool an automotive system, but there's NO WAY he'd install it.

    There are R12 substitutes called "Hot shot" that they use for systems that cannot be converted to R134.

  5. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 646

    Jack E/NJ
    from NJ

    Probably would only take a quart or so of propane to fill a system --- 2 Coleman or Bernz cylinders

    Jack E/NJ
  6. ever since my neighbors house blew off the face of the earth, i think about propane differently. there is r-12 still around if you look.
  7. cayager
    Joined: Feb 10, 2012
    Posts: 293


    heard of it but in my opinion there are to many things to go wrong, under the hood.
  8. cshades
    Joined: Sep 2, 2011
    Posts: 505

    from wi

    Propane will cool in an a/c system.It also will piss off anyone who works on the system later when it wrecks their recovery equip. it also isnt really good for the system. Also as was pointed out before it is dangerous, not only in an accident but if it develops a leak at the right time and place, it will go boom. 12 is still out there you just have to look, some shops still have recovered R12 in their machines. I say put in the right stuff or upgrade it to 134 and live longer.
  9. Frankie47
    Joined: Dec 20, 2008
    Posts: 1,863

    from omaha ne.

    All kinds of cars run on propane is an a\c more dangerous than that?
  10. funk 49
    Joined: Nov 14, 2010
    Posts: 242

    funk 49

    I also know of this being done,but would never recomend it. Spend the money on r-12
    or convert it over and you will be way ahead of the game with alot less worries.
  11. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,792


    First, why would you? Second, while it MAY work, it's got. "Hey! Watch this.", written all over it.
  12. The propane fuel system (if properly designed and installed) is designed to contain the propane in the event of a crash (at least to a point, nothing can 100% protect it from a catastrophic failure), where as the R-12 A/C system was designed to hold a (relatively) non-volitle gas. Compare how many ruptured fuel tanks you see in rear end collisions to how many busted condensers you see in front end collisions.

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  13. borderboy1971
    Joined: Oct 20, 2008
    Posts: 743

    from Canada

    Be aware also that almost all of the aftermarket "top up" type kits are using a propane or butane mix. They do work for cooling but I wouldn't recommend it. Here's something to think about... Suppose the evaporator had a leak in it that leaks into the passenger compartment. propane is heavier than air, so it will settle near the floor boards first. In most vehicles the signal flasher or relays for power seats or seat motors etc, are at seat level or lower. These controls can emit a spark.
  14. fsae0607
    Joined: Apr 3, 2012
    Posts: 871


    You have the very vulnerable condenser up front. A good frontal collision will rupture it.
  15. whiskerz
    Joined: Jul 7, 2011
    Posts: 148

    from Ga.

    Was discussed in an AC class I took. Contaminates freon recovery machines and the fire issues are discussed already. It is easy enough to find R-12
  16. Frankie47
    Joined: Dec 20, 2008
    Posts: 1,863

    from omaha ne.

    Thank you!
  17. KRB52
    Joined: Jul 9, 2011
    Posts: 1,025

    from Conneticut

    I have studied some HVAC/R; propane is used as a refrigerant. There are some companies in Europe that are now using it in home refrigerators and such. Yes, it basicly is the same propane you use in the gas grill. Does it work? In a system designed for it, yes, as well as anything else. Do I personally think it's a good idea to use it in an automotive system? Heck, no.

    Check with a qualified technician about your system.
  18. fsae0607
    Joined: Apr 3, 2012
    Posts: 871


    Yes from a thermodynamic point of view, propane works good as refrigerant. So does ammonia. Most big cooling system (like the freezer section at Costco for example) use ammonia and it works good.

    For automotive, you need to use something [relatively] non-flammable and non-toxic. The "R" series refrigerants fit the bill.
  19. tommyd
    Joined: Dec 10, 2010
    Posts: 11,328

    from South Indy

    Now that's FUNNY!:p
  20. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    Was that the New Milford house last year, or the one at Big Al's?
  21. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope

    R134 is at least as flammable as propane.
  22. Here is a copy and paste of my son's A/C experience using yet another alternative refrigerant:

    After I fixed my last compressor, I charged up the system with R152a, the air duster and man does it work good. The warm months have passed, but I did get to test my AC for a couple months when it was rocking 100+ *F outside with tons of Oklahoma humidity to boot. Even with the ridiculous equatorial style heat and humidity, my average vent temperatures were ~34-38*F..... This was taken with a regular style mercury thermo.... Now I also have a infrared thermometer gun-thingey and using it, I measured the temperature of the HVAC ductwork itself and the ductwork was never any higher than 15*F..... (+/- 5*).

    To fully utilize the awesomely performing and awesomely cheap refrigerant, I did make a couple of supporting modifications to help boost the system performance.

    1. I installed two shut off valves for the heater core, one for inlet and one for outlet that way the core was totally isolated from hot coolant.

    2. The more important of these two mods is definitely this one - I installed an *adjustable* low pressure cycling switch from I believe a mid 90's Corvette and was able to really dial in the compressor's cycling regimen. The first time I started playing with adjusting the cycling switch I got it too cold and froze the evaporator core SOLID..... A little tweaking on it and the compressor cycles off just as a very light layer of frost develops all over the lines, the dryer and the evaporator. This is just where I feel it performed best; getting as cold as possible without solidly freezing the evaporator.

    If you do your research you will find that R152a has a very similar temperature vs. pressure curve to the ol' liquid gold R12.... No wonder this stuff works sooooo damn good. Never wasting time (or money) on R134a again.......




  23. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771


    I have a 94 Chevy pickup I converted to 134A and it blows 26 degrees out the center vent going down the highway. 134a conversion isn't that hard to make work. My 66 Impala was converted back in 2001 and it worked great until about 5 years later when the POA siezed up. When I fix it this summer I'm changing the condenser and replacing the POA and recharging with 134a again.
  24. mopar57
    Joined: Apr 24, 2012
    Posts: 85


    I do commercial and industrial a/c and do work on my cars a/c.I would recommend the 134a to replace the r12. I have added the 134a cans with oil in them on old r12 systems and have had them work fine without adding a retrofit kit on a few cars. just my .02.
  25. the house was 4 doors down [about 3/4 mile] it knocked the lamp shades off a chandelier in our house:eek:
    Gregs shop was another propane disaster that turned a building to dust.
  26. Corn Fed
    Joined: May 16, 2002
    Posts: 2,953

    Corn Fed

    What's the going rate for the small pint sized R12 cans? Are there any legal issues buying, selling, or using it?
  27. Jimm56
    Joined: Aug 27, 2010
    Posts: 170


    Last time I looked, it was around $30 a can. Legally, you have to have a licence and work at an a/c shop.
  28. YMMOT
    Joined: Dec 17, 2008
    Posts: 2

    from IL

    hot shot also has propane in the mix plus butane butalene propane has a flas point of -44 that is Constance below
  29. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    I heard (& felt) that shop in front of Big Al's blow up. Hell of an explosion considering I'm a few miles away...

    That house explosion was tragic. Glad I have oil heat
  30. wsdad
    Joined: Dec 31, 2005
    Posts: 1,258


    Get, "Hot Shot" brand at any appliance parts store. It's R414. It was made to be a direct substitute for R12. No need to change the compressor oil or do anything else to the AC system. Follow the directions on the can. They say to charge it as a liquid (turn the can upsidedown) and use 20% less R414 than R12. It has been working perfectly in refrigerators and cars for roughly 25 years now. I have personally used it more times than I can remember or count.
    That's very interesting that propane can be used as a refrigerant. I may do some research and try rigging something up in my dad's cooler that he uses to butcher and age beef. I wonder if it attracts water like most regular refrigerants do?

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