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

[Hacker J]

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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