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A/C System

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Young Buck, May 13, 2020.

  1. Young Buck

    Young Buck Registered User

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    Moving to Florida from California and looking to get my A/C system in top notch working order. I've read slot of mixed things here on the forum. I do not want to do this on the cheap or cut any corners. Not my area of expertise so I am going to have it professionally done with All the right Motorcraft parts and R12. Before I take it to the shop I was hoping to get wisdom from those you who have been down this road before. System seems to be in good condition but If I end up needing to replace enough components I may consider redoing the system to take r134. If I do go this route I will use all 1994 components and do it the right way. I've heard bad things about shoving 134 where it doesn't belong. Anyway, Looking forward to your input. Just trying to wrap my head around what I am walking into. Thanks guys.
     
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  2. aggiediesel01

    aggiediesel01 Full Access Member

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    Is your system in working order now? Maybe just low on refrigerant? Has it not already been converted to r134? If your system is in original working order with reminants of r12 you might even have trouble finding a shop willing to work on it. By now most places don't have a recovery tank or charging equipment for r12 and of course it's bad news for them to vent it so if it's still got r12 in it you'll likely have to call around to find a place that can suck it down. There are several r-12 equivalents on the market now with fairly long term track records of effectiveness. Although it was very effective I would stay away from r12 simply from the cost stand point. For the cost of just the refrigerant charging you could buy several new major components of the rest of the system. If you are planning to replace several if not all of the system components then buy the appropriate replacements for r134 or r12 equivalent and and in a year or so when it's time to fill it up again you'll be many dollars ahead.

    As for updating to '94 components and your truck being an '83; do you have the short wide radiator or the narrower but much taller radiator. You need to check because the condenser connection points have to fit around the radiator and in 94 they only used the narrower but tall radiator. I assume that since your signature says you've got a turbo 7.3 in it you've also got a serpentine belt system? If not the '94 compressor is only available for the serp system. Not that you have to upgrade to the serp belt but you'll have to use a '92 compressor with who knows what year clutch on it to the the belt alignment correct.
     
    Last edited: May 13, 2020
  3. franklin2

    franklin2 Full Access Member

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    The "right way" is grey area statement. There are many different ways to do things and they work fine.

    And the previous poster is correct, I ran into that. I tried to do the right thing and get some r12 recovered, no one would do it except one guy, and he wanted an astronomical price. I asked him what the score was, I figured everyone would be jumping to get some r12. He said he has a tank sitting in the corner, he puts it in there and it just sits there, he can't do anything with it, no one wants it.

    I called around the local junkyards, certainly they have a recovery machine with all those old cars they get in? Nope. And when I started asking them about it, they kind of shut up, I guess they thought I was the EPA or something.
     
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  4. rhythim

    rhythim Registered User

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    The only way I'd go with R12 is if you did what I did and replaced Every. Single. Component. in an already completely discharged/empty system, and then pressure test with nitrogen to be 1000% sure it's leak-free before charging, otherwise bite the bullet and convert to 134a because it's much more economical in the long run. You're already talking around $500 just for all the parts, going aftermarket, with the compressor being the bulk of that. If converting to R134a I recommend adding an electric pusher fan to the front of the condenser wired to run whenever the compressor is activated. Most condenser manufacturers have gone away from the old tube/fin serpentine construction to a flat tube parallel or piccolo-flow design that works better with R134a, but the additional fan still helps, particularly at low speeds.

    3 things: 1) I've been certified on mobile A/C systems for 24 years and have my own equipment for personal use. 2) I bought and stashed an undisclosed amount of R12 decades ago before it was phased out for my own usage. My truck is now the only thing I have old enough to use it. 3) R12 can still be found if you look hard enough and are lucky, but the cost will not be cheap, or even reasonable (I paid $35 for the last can I bought retail, and that was literally 20 years ago). System capacity on my '85 was listed at about 52oz on the sticker on the rad support if memory serves, so just over 4 cans. Also agree with other commenters in that it will be difficult to find a shop willing to use it.

    All of that said, the air in my truck will freeze you out of the cab, but I wouldn't have touched it had it been somebody else's truck.

    Sent from my SM-G988U using Tapatalk
     
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  5. Booyah45828

    Booyah45828 Full Access Member

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    What rhythim said.

    We still have the r12 recovery machine up in the loft, along with the can piercer and the gauge set. No idea if any of it works anymore, it hasn't been used in over a decade and has nearly an inch of dust on it. The recovery tank likely still has r12 in it. I don't know of anyone that would purchase it if I wanted to get rid of it, it seems to be expensive to purchase, but a liability to sell it.

    The last time I priced cans of r12 was about 8 years ago. A customer restored an old corvette with factory ac. At that time napa wanted 50+ a can for it. Since it was a restoration, and everything was new/reman'd, we flushed and converted the system to r134A.
     
  6. mexicanjoe

    mexicanjoe Full Access Member

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    my '89 had R-12, and was converted to R134a on the cheap. I changed the orifice tube, the connections and evacuated the system, while leaving the drier/accumulator intact ( well, my buddy did)... It held vacuum for 2 hours and then we added the oil charge and freon. On a hot day in west texas my temp gauges show 40* at the vents... Maybe I got lucky, maybe it will crater today, i dont know. But my swap was uneventful and its still working 2 years later.
     
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  7. franklin2

    franklin2 Full Access Member

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    That's how most of them go. And if you make a mistake and miss something and have a small leak, you can fix it, go down to walmart and get some cans of r134a for $5 per can, stick it in and try it again.

    And if you are a tree hugger, you might has well go 134a. If you do have a leak it's not supposed to harm the environment like the r12. With these old trucks it's not if they leak but when they are going to leak.
     
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  8. chris142

    chris142 Full Access Member

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    These systems work well on R134a. This is one of the reasons I bought mine.
     
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  9. rhkcommander

    rhkcommander Full Access Member

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    All systems leak sooner or later, when the orings get brittle. There are some refrigerants that work better but are flammable, r600 I think is one. Some people scoff at flammable refrigerants but a lot of the other crap in your vehicle is too...
     
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  10. Macrobb

    Macrobb Full Access Member

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    Yeah... Unofficially, you can look into the "HC-12" blends that are out there; basically a propane mixture that's, well, flammable... but definitely does the job.
    EPA says you can't do this, though, so I obviously can't recommend it.
    Another name for it is R290. R600a is basically butane, and is actually used in some smaller cheap consumer chest freezers - it's got a higher boiling temperature, so the pressures would probably be lower than R12... not sure how well it would work compared to R12 or HC12.
     
  11. BeastMaster

    BeastMaster Full Access Member

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    Anyone have advice on running R290?

    I hear R290 and ATF are compatible, but I wonder what kind of material the seals should be made of. I am just getting so fed up with all this licensing stuff that if I can get commonly available stuff to do the job...
     
    Last edited: May 15, 2020
  12. Macrobb

    Macrobb Full Access Member

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    I'd bet that anything that would work with R12 and mineral oil would probably do the job fine...
     
  13. rhkcommander

    rhkcommander Full Access Member

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    If you use something other than mineral, use POE. It bridges R12 and R134a. Not sure about all the newer fancy refrigerants. Hell there were some guys using cans of duster or something similar to charge their systems, it might have been r1234a or something inside.


    I would just re- oring everything, orifice tube (which can be a pain in the ass) assuming not Txv (90% sure I dont think these trucks use txv but it's been a while), and dryer swap. Flush the old oil, new hoses wouldnt hurt. New high n low caps. Reuse condenser, evap, compressor. Add a fan to the condenser for even better performance. Oil n r134a or whatever you choose. You'll be icy cold in no time with a system that'll last unless you dont run it and the rings go brittle. My 2 cents.

    Harbor garbage has gauge sets that are ok, and vacuum pumps that work by venturi. It's better than nothing, I've seen lots of junkyard repairs that do ok too where guys will skip it all and just charge it up, I dont recommend that though. If you yet bored you can make your own vacuum pump from an old fridge compressor and some brazing. Just gotta oil it up. Atmosphere in the lines is your enemy, it'll turn the system acidic and kill your compressor. The dryer will prevent that some but if it's a new charge I'd swap it for peace of mind. If a job is worth doing, it's worth doing right. You could probably charge it up and be done and go for years if an oring hasn't cracked, or you could have a snapped off orifice tube and get crappy performance and have wasted all that time if you skip steps.

    Not sure what you meant by ATF?

    Either way, add a shot of dye, it'll make your life easier WHEN, not IF you have a leak if you dont have a sniffer. Add an electric fan that switches on with compressor and you'll freeze your nuts off with r12 or r134a or whatever else you choose.
     
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  14. Macrobb

    Macrobb Full Access Member

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    Turns out that if you need a "mineral oil" lubricant that will work with the OBS compressors(which are very tight and have lots of aluminum and are very easy to score), ATF seems to do the trick. High temp, synthetic oil of a low viscosity for easy flowing through the system.
    The "AC Mineral oil" I bought at the parts store... did not work. It was too thick.
     
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  15. rhkcommander

    rhkcommander Full Access Member

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    Fantastic. What cant ATF cure in these old trucks :Thumbs Up
     
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  16. BeastMaster

    BeastMaster Full Access Member

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    "ATF"="Automatic Transmission Fluid"

    And

    R290 is Propane... Barbeque gas, Hank Hill style... ( King of the Hill TV animated comedy ).

    The stuff sold as R290 is reportedly a higher grade, but I know for a fact our church was cooled for 50 years with the plain old barbeque stuff. We used it to make a big block of ice, at night, then melted the ice and circulated the chilled water to cool the sanctuary during the day. We never used the expensive stuff. Just barbeque gas. Not much more than was in a typical residential barbeque. We kept everything that might possibly catch fire outside in cinder block outhouses. Including the ice house.

    Beautiful design. A guy old enough to be my grandpa built it.
     
    Last edited: May 15, 2020

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