wanted: someone who can work on a R12 system in College Station area.

Discussion in '6.9L IH & 7.3L IDI Diesels' started by towcat, May 7, 2018.

  1. raydav

    raydav Full Access Member

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    I have been using Envirosafe for well over a decade, mostly in old Fords without changing anything in the system. In 2007 I was driving my newly acquired 2001 PSD home when an adjacent hose clamp finished wearing a hole in a steel AC line. I brazed the hole and charged with Envirosafe. That worked fine. Recently the compressor failed. I replaced it and again charged with Envirosafe.

    It has been stated that Envirosafe is propane plus butane. Anyone know the ratio? It seems to still be expensive considering that the components are a few dollars a gallon. But it is in a handy container, it works, the cost per system is small, so I will keep using it. I recently bought two 30#.

    But, the only thing I have used for leak testing a newly assembled system is air. What about using propane for testing? It should be a more realistic test, will activate a gas sniffer, is easier to get and a lot less cost than Envirosafe when it leaks out.
     
    Last edited: May 16, 2018
  2. 79jasper

    79jasper Chickenhawk

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    Many like nitrogen for pressure testing.

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  3. raydav

    raydav Full Access Member

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    Can an auto AC system produce a full Carnot cycle using nitrogen?
     
  4. 79jasper

    79jasper Chickenhawk

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    A what?

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  5. raydav

    raydav Full Access Member

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    A Carnot cycle is the phases that a refrigerant goes thru in an AC system - gas to liquid and back.

    Meanwhile, straight propane does seem to be working. I was satisfied with an air test. I added oil and dye and charged with propane in hopes that the propane will circulate the dye. The sight glass shows liquid flowing and the pipe after the expansion orifice is very cold.

    I'll give it a few days. If the pressure holds I will charge with Envirosafe.
     
  6. Booyah45828

    Booyah45828 Registered User

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    No, not even close to the pressures required to get to the liquid phase of nitrogen.

    It's used because it is cheap and moisture free, which is a biggie when using any sort of hfc refrigerant.

    Add 100 psi to the system, and if you have a leak, it will show on the gauges in a matter of minutes.

    Refrigerant, or anything going through a phase change in the system, will take a significant amount of time due to the boiling off of refrigerant to maintain the psi. Once all the refrigerant is boiled off, then the pressure will finally drop indicating a leak.
     
  7. DrCharles

    DrCharles Full Access Member

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    True. That's why you only put just enough in to make pressure in the system, and not a surplus of liquid ;) Dry nitrogen's great, if you have a tank handy...
     
  8. 79jasper

    79jasper Chickenhawk

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    Yeah, the nitrogen is just for testing purposes. Hear it helps remove moisture as well.


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  9. raydav

    raydav Full Access Member

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    I long ago went to HC.

    Will nitrogen show a small leak quicker than air?

    How good is nitrogen at distributing dye?
     
  10. chris142

    chris142 Full Access Member

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    You only pressurize it with nitrogen to find leaks using soap.you don't run the system with it in there.
     
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  11. raydav

    raydav Full Access Member

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    Soap will only find big leaks, and not even all of those. I had a leak in the compressor shaft. I had it covered is soap suds. But I did not pinpoint the leak until I pressurized the compressor and submerged it water. The dye did not work either because it never flowed out far enough to see.

    I am still not clear on what nitrogen will do better than air, which is mostly nitrogen. My air compressor air is filtered.

    And after air check I need something cheap to distribute dye.
     
  12. david85

    david85 Full Access Member

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    Yeah, I saw the limit of soap bubbles too when I was working on my Dad's ranger. I recharged it shortly after he brought it home and it worked great from day one. The system would freeze you out of the truck no matter how hot it was outisde. But near the end of the season it started leaking at the compressor shaft. I was able to get a replacement seal from rockauto, but it still leaked and I was never able to figure out 100% for sure if it was still a leak at the shaft or somewhere else. I'm thinking to just get a new compressor.
     
  13. 79jasper

    79jasper Chickenhawk

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    Some "snoop" would probably work better. I would bet it has to do with the surface being oily. The soap won't exactly stick to it like it should.

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  14. chris142

    chris142 Full Access Member

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    Your filtered air is fine. Most shops just plug the air hose on to the system and flood it with moisture. We use [email protected] 200 psi per law.
     
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  15. Macrobb

    Macrobb Full Access Member

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    If you got your propane from, say, a barbecue tank(5 gallon), remember: it's LPG, not propane.
    The difference is that LPG is a mixture of propane, butane and a couple other things. Depending on the time of the year you get your tank filled, the mix varies a bit.
    Which is why it isn't much different from envirosafe...
     

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