[Supras] No AC on 86.5 MkIII w/ R134A conversion

[Jim Wooden]

Thanks Jon!

I was told that AFTER conversion there would be bubbles in the sight 
glass as to clear the bubbles would result in an over-fill when using 134A.
Is that BS?
I have to say that even when it was working correctly there were 
still bubbles after conversion.

At one time I had a chart for R-12 that showed typical hi & low side 
pressures vs. operating conditions ... still not ideal but would at 
least get a guy close....

Thanks for your help!
Jim



At 02:34 PM 3/28/2008, Hacker J wrote:

>The pressures will depend on heat load, humidity, compressor speed, 
>and ambient temperatures, so
>nothing can really be said there.
>
>The sight glass needs to be free of bubbles during operation 
>indicating that the high side is
>fully condensed.  Toyota has never released any data on the 
>subcooling temp, and the superheat is
>set by the TXV in the evaporator, so really the sight glass is all 
>you can go by.
>
>Jon
>90T
>
>
>
> > > From: Jim Wooden <Jim at WoodenU.com>
> > To: Supras at supras.com
> > Date: Fri, 28 Mar 2008 09:02:15 -0400
> > Subject: [Supras] No AC on 86.5 MkIII w/ R134A conversion
> >
> >
> > Well some years back I converted my AC to the R134A as, at the time,
> > R12 was very expensive and I had some leaking o-rings that required
> > disassembly of the system.
> >
> > On the advice of a mechanic buddy that had done a number of these
> > conversions we did the "simple" conversion which consisted of adding
> > PAG oil and "special additives" via a kit from Quest then recharged
> > with recommended amt of R134A
> >
> > Worked fine for two years then just didn't seem nearly as cold any more.
> > I took it back to him and, finding no serious leaks, he just hooked
> > up the AC machine pumped it down and loaded a fresh charge.
> > Well... its two years later AGAIN, and although there is still some
> > charge in the system (sight glass shows pretty full) I get ZERO cold air.
> >
> > I have heard the R134A cars (esp. the conversions) are much more
> > sensitive to being low on charge, and that could be the case here...
> >
> > Does anybody have the recommended high-side/low-side pressures for a
> > MkIII R134A conversion handy?
> >
> > Other suggestions appreciated also  ;-)
> >
> > Thanks,
> > Jim W.
> > original owner 1986.5 MkIII
> >
>
>
>
> 
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