"" wrote:

You might beable to purchase adaptors (or new hoses) to be able to use
new gauges but newer gauges would be a good invetment. SOme R12
systems do poorly with R134a which does have less cooling capacity and
runs at a higher pressure too. (newer car compensate for this with
bigger condensors and evaporators with a different compressor and
increased refridgerant flow. Envirsafe or ES12 or the like works real
good in old R12 systems and is much better than R134 for this uses and
even better than R12. THe only reason it is not EPA aprroved is
because it is hydro carbon based so it can burn (so does gas and you
have a lot of that in car) but not in a enclosed system and there is
not enough in car to be a big hazard in a wreck or such. R134 leak
detectors will not detect ES12. Also ES 12 is compatable with existing
R12 oil, R134 is not and a specail oil has to be added to the system
to bind to old oil to let it be carried through system by R134
properly which results in a slight oil overcharge too unless you are
starting from scratch.  Finailly, R134 is not very environment frendly
at all though it is better than R12 obout ozone it is still has a life
in atmosphere of well over 15 years why ES12/envirosafe is gone in
less than a year with no lasting effect. When my supply of R12 runs
out, I plan to use it in my R12 cars if need be as I tried a few car
conversions with R134 and I was not too pleased.