The only other way I know of, without someone testing the contents, is
that when a system is changed to R134 the person doing the changover is
"SUPPOSED" to affix a sticker nearby showing that it was changed and
what type of oil (Pag or Ester) was used.

My sticker is on the black box cover against the engine compartment
firewall ... looking right at me when I open the engine hatch.

Mike
'85 Westy with R134

James V wrote:
> Is it possible to tell if the AC is R12 or R134, BESIDES the low/high side
> fittings?
>
> When I purchased my 88 Westy over a year ago, the previous owner (whom I've
> found no reason not to trust), said the van had previously (by the prior
> owner) been converted to R134.  But when I went to fill, I noticed that it
> did not have the R134 low side fitting.
>
> I contacted the seller, and he recalled that he thinks he filled it, and
> then may have removed the fitting for use on another van.
>
> So then I checked the high-side fitting, and that does not have the R134
> fitting either.  Weird.
>
> So, is there a way for me to tell what I have in there?  If not, what should
> my next course of action be, assuming there's the possibility that R134 may
> have been added to an R12 system?
>
> Thanks,
>
> James V
> 88 Westy
>