AC - R12 to R134a

Discussion in 'Technical' started by Pepper, Jan 18, 2017.

  1. Pepper

    Pepper 1991 N/A Slicktop

    Keeping the car... AC's got a leak which needs fixing before I do anything else.
    Auto-elec wants to charge me $1400 to pull/recondition/regas.

    Seems like insane labour costs, as the drier replacement and seals are quite cheap.

    Currently sourcing parts to give it a go myself:

    Not incredibly confident though.
    Have any good advice for me?

    This should be the drier I'm after:

    Anyone keen to do this for me if I provide the parts and adequate $$$?
    Last edited: Jan 18, 2017
  2. Pepper

    Pepper 1991 N/A Slicktop

    Did some more reading and made a few more calls.
    Two more estimates for $1300.

    Am I underestimating the labour involved?
  3. Pepper

    Pepper 1991 N/A Slicktop

    Nevermind lads, will go ahead with sale as-is.

    QLDZDR ID=David

    For that amount of money, I hope they are doing more than this.
  5. Mitch

    Mitch Has one gear: GO

    R12 ain't cheap, if you can get your hands on it.
    R134a should be had (wholesale) for no more than 20clams per kilo... check the weights in the FSM, but the z32 shouldn't take more than 600g iirc.

    The real cost is you paying for their work. Not just anyone can crack into a refrigerant system, you need ARC licences to handle refrigerant, and doing the work yourself and not having those licences would be a hefty fine if caught. It's a 'hole in the ozone layer' kinda thing.

    Cheapest way out for you would be to get a mobile guy out to evacuate the system (reclaim the R12). Then you'd do all the work you need to, then get the mobile guy back out to vac the system, check for leaks, and rinse/repeat until the system is good to recharge.

    Refrigeration is a black art. If you have the coin, spend it and drive in / drive out.
  6. tuff

    tuff Member

    **** r12, hychill is the equivalent, drops straight into r12 system, same oil etc. Most places will regas with dye for under $200. If you are confident that the system has no leaks than just go that way. If you have concern there might be leaks than main things to replace are receiver/dryer, compressor line o-rings and low pressure switch. These can be had at a reasonable cost, then get it vac tested before they gas it.

    If compressor is knackered then be prepared to bend over and receive the pineapple. Don't get the compressor rebuilt, if you really have to get a new compressor, 8/10 rebuilt compressor will eventually leak/fail is what I've been told by 4 reputable a/c specialist now.
  7. Mitch

    Mitch Has one gear: GO

    Yeah man, I've heard of R12 prices bing around $1K per kilo. It's a prohibited refrigerant, so supply / demand kicked its arse. It's a freon refrigerant.
    R12 was replaced by R134a, R134a and hychill are equivalents, but the flammability aspect is a concern- especially so in an older system. Propane (which hychill is made of) runs a higher pressure too... so more risk of opening up problems in a system where they may not presently exist.
  8. tuff

    tuff Member

    True about the pressures.

    Hychil do have a gas compatible/same to suit the r12 system. My house a/c runs on it and one of my zeds is getting gassed with it this fortnight at my local auto spark.
  9. tassuperkart

    tassuperkart Its a lie I tell you!

    Ahhhh... no it doesnt mate.
    Discharge (head) pressures are lower than R12 and r134.

    Lower head pressures = lower head temps = lower power drain = :D.

    The issue of flammability, altho there, isnt really the issue its often and sometimes hysterically made out to be.

    Propane/Butane gas mix (Hychill) has a surprisingly high flash point. Pretty much needs a naked flame or a good fat spark to light up. Additionally, catastrophic failures of AC systems are more or less non-existant where all the gas will catastrophically discharge to create a fire issue..

    Failures are pretty much limited to hose splits, leaking O-rings or minor condenser/evaporator leaks from either corrosion or impact damage.

    Nobody thinks twice about carting around 45 kilos of LPG in the boot and a bloody great liquid discharge line into the engine bay yet the get all bent out of shape about carrying around a few hundred GRAMS of gas in an AC sytem... really?

  10. brisz

    brisz Well-Known Member

    Another reason why we need JDM manual

    The manual is US/International and mentions a Zexel DKS-16H compressor which we do not have on JDM TT and goes on to mention 200ml of SUNISO 5GS oil and .75-.85 Kg R12.

    Someone must have a JDM manual.
  11. QLDZDR

    QLDZDR ID=David

    If ALL your gas has leaked out and that also means your compressor clutch won't engage, then you probably need to replace the valves and more. Looks like tyre valves.

    But you are wondering if the rest of the system works?

    You might be lucky and find that the thread under the tip of your PRIMUS torch is the same as the low end valve of your AC.

    Some guy tested his system with a Hychill/propane-butane type mix. Coincidentally the same propane/butane mix as LPG in some states. The AC was working. To rule out the valve ends for leaks, a suitable UNC thread bolt with teflon tape and locked down with a nut to be sure, was added in place of the plastic caps.

    None of this DIY dodgy testing will be a problem when the car goes to the AC guy, because they evacuate the AC of any gas before they regas your AC.
  12. tassuperkart

    tassuperkart Its a lie I tell you!

    Hychill isnt just "the same propane/butane mix as LPG in some states"..... LPG is largely propane gas AKA R600 AKA barbecue gas.
    Butane (R290) is a different animal alltogether.
    Hychill mixes "LPG" with Butane, in a (circa) 75/25% mix as it closely emulates the performance of R12 (CFC) refrigerant systems.

    The plastic valve caps have an incorporated rubber seal so winding it bolts, nuts, teflon tape et-al is a pretty pointless exercise. Gas loss from leaking charge valves is so rare its hardly worth mentioning.
    The valves are simply an automotive type tyre (Schraeder) valve and unless physically damaged, will last the lifetime of the car.
    They are often routinely replaced at major system services as they are worth only a few cents each.

    I use plain old R600 (LPG) in my AC systems using a more suitable Synthetic lubricant designed for hydrocarbon refrigerants.
    I made a simple vacuum pump out of an old electric fridge motor and a simple adapter to attach the (inverted) barby bottle to the charging guages.
    Hydrocarbon refrigerants are so superior to R134a its beyond funny.
    Being far more compressible, considerably less energy is drawn from the engine and the gas is so "cold" that the compressor runs for less than half the time before the evap. core thermostat cuts the compressor out to prevent evap. core icing.
    Even with the fan running flat out and the air recirc door set to "Fresh" on a humid day with engine idling, my compressor is still tripping in and out and the compressor never runs much longer than 30 to 40 seconds per cycle.
    Using traditional (R12/R134a) refrigerants, the compressor would run full time on fan position 3 and 4.
    The only downside to this is the constant and fairly rapid cycling of vent temps over the hysteresis of the thermostat. Im pretty sure I can live with that LOL!

    Why more people dont make the change to hydrocarbon refrigerants (Hychill) is a complete and utter mystery to me given its a straight "drop in" replacement for R134a subject to a system flush and a few ounces of lubricant.
    Central QLD Z, Zeo and MagicMike like this.

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