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1966 Olds Toronado A/C

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  • #16
    I think the "powers that be" 1st made it a hard rule that auto A/C can't use flammable (class B) refrigerants. Then they wanted non ozone attacking, now they want non climate warming.
    The problem is: those three requirements are mutually exclusive. Any two may be but all three no. They have now started backing away from the non flammable and saying low flammable is ok. That opens the door to things that were verboten only a few years ago. I think 134a is slightly less flammable than 152a, but both support combustion to some degree.
    To get around their own rules they have made a new class of "slightly flammable" that can be used.
    When the choice came to pick between 134a and 152a the difference in flammability and the fact both required different oil, 134a won that battle. It does seam like 152a would be better in retrofits, but I'm not sure. Certainly there is something to be said for "going with the crowd" in terms of availability.


    • #17
      I know this is an older thread, but I came across this statement while looking up other stuff and it applies to this refrigerant:
      HFC-152a is an A2 flammable refrigerant as classified by ASHRAE 34 and should be used only with a secondary loop application. However, until MAC systems are developed to use HFC-152a (R-152a), no SAE Standards for system design, service equipment or service procedures have been established. The R-152a service fittings described within this Standard were established as part of the industry’s evaluation of replacement refrigerants and are maintained for future design guidance and to prevent potential refrigerant cross contamination


      • #18
        Sorry guys, I didn't realize there had been more replies. I didn't mean to be rude.

        I charged the system with R134A (by weight equivalent from R12) and it worked acceptably, although cooling really suffers when the car is at a stop (there is a large gap between radiator and condenser, with nothing to prevent air from the mechanical fan going around the condenser), so this lack of air flow through the condenser will need to be addressed.

        Ambient temperatures have dropped, so this will have to wait until next year, but I still haven't given up on R152A. After I address my airflow problem, I'll lower the POA setpoint to 23PSI and report back with my results.

        Thank you all who responded and my apologies for not following up.
        Last edited by Mikel; 1 day ago.


        • #19
          When charging by weight, 134a should be 75%-80% of the R12 weight, so you may be a little overcharged. Also 134A also required a lower POA valve setting, around 26 psi IIRC.