Converting K5 Blazer A/C to R-12

Discussion in 'Tech Discussion' started by ripple1973, Jul 22, 2018.

  1. ripple1973

    ripple1973 Junior Member

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    Hello group I am getting ready to convert my R134 system back to an R12 system would a flush be necessary to complete this? Also i am assuming that I will not need to change compressor, which is a year old. I am just fed up with the poor performance of a R134 system in my blazer. I tried everything parallel flow condenser. It sucks to not have a good a/c in Texas.


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  2. smoothandlow84

    smoothandlow84 I'd rather be draggin' frame

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    Yes you will have to flush. Once you open the system it becomes contaminated. The compressor from what I have been told should be fine once flushed. You should also get a new oriface tube as they too get clogged and contaminated...at $5 its cheap insurance. These evaporators operate more efficiently with r12 than with r134. Before I went full on r134a from r12, I wasnt able to source a viable compressor since they are all built to use with r134a. Fwiw my system cools down to 40 degrees without any problems other than the fan not blowing at the force like my late 3 year old truck.
     
  3. GMFORLIFE

    GMFORLIFE Full Access Member

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    You wont be able to afford R12.
     
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  4. smoothandlow84

    smoothandlow84 I'd rather be draggin' frame

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    Going price of r12 here in az is hovering around $40 per 12 oz can
     
  5. ripple1973

    ripple1973 Junior Member

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    40 bucks can is so worth it. It is a daily driver and it is 105 today out today in South Texas and this 134a is not cutting it and I hear some horror stories about people using r12 replacement product that are basically propane.

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  6. 1987 GMC Jimmy

    1987 GMC Jimmy Full Access Member

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    I think that’s Freon 12 that you’re talking about. I hope the conversion back goes well. I wish it was thirty years ago, and R12 was still the norm. The price gouged stuff (R1234yf) that new cars have to switch to by 2020 (?) seems more complaint worthy so I won’t talk too badly about R134a.
     
  7. yevgenievich

    yevgenievich Full Access Member

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    With a bit of work, stock system can handle all but parking lot idle with 134 freon when outside temp is aproaching 45*C. After complete flush and new orifice tube/dryer/oil fill should be fine for use with r12
     
    Last edited: Jul 23, 2018
  8. smoothandlow84

    smoothandlow84 I'd rather be draggin' frame

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    You will need 4 to 5 cans for the complete system....so figure on $200, that is of course unless you have a leak
     
  9. highdesertrange

    highdesertrange Full Access Member

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    replace your orifice tube and your receiver dryer.

    have you tried an aftermarket fan in front of you condenser? that usually works for the ones that have been converted to 134.

    highdesertranger
     
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  10. yevgenievich

    yevgenievich Full Access Member

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    Red tube. Aux fan, and parallel flow condenser were almost enough for my suburban. For a converted halfton short bed, just blue orifice tube and clean stock condenser was enough for texas heat. Both with 134. 89 TA blows 5* C in 42* weather in light traffic, 10*C in heavy traffic.
     
  11. Goldie Driver

    Goldie Driver Full Access Member

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    Is this blue orifice tube a generic part that can be bought at the parts store?
    I am thinking I will try that as the ac sucks on traffic.

    Ironically, the engine cools off when in traffic- makes me wonder if the lower hose might be collapsing...

    Or if I need a 180 stat.

    Fun times!
     
  12. yevgenievich

    yevgenievich Full Access Member

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    95 ford f150 would pull up blue orifice tube. But before making changes you are welcome to post exact current configuration, out side vs vent temp information and low side/high side pressures during operation. Might help to ensure everything is doing its best by going through everything.
     
    Last edited: Jul 27, 2018
  13. yevgenievich

    yevgenievich Full Access Member

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    Also if engine is getting too cool at idle for some reason, the clutch fan might stop pulling much air reducing efficiency of the condenser. Aux fan helps decently as well for idle operation.
     
  14. ripple1973

    ripple1973 Junior Member

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    I do have a parallel condenser and got a new fan clutch. Do yall have the can or flat compressor?

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  15. ripple1973

    ripple1973 Junior Member

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    Or in yalls opinion do you think that matters

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