How would I know what type my vehicle currently uses? Does it say on the
A/C unit? Is there a certain year it switched over? I currently own a 98
s-blazer & 98 K1500. Would these use the R12 or the 134?

Dave
"do_not_spam_me" > wrote in message
om...
> "Spiderman" > wrote in message
>...
>
> > I have a 1989 Chevy S10 Blazer that blows out warm A/C. It's
> > low on R12 so the compressor just cycles on/off. I'm gonna top
> > it off with R12. Is a gauge necessary or can I just play it
> > "by air".
>
> Try the forums at www.aircondition.com, a place dedicated to car A/C.
>
> People who know better than me are going to hate what I'm about to
> say, but if nothing else is wrong with the A/C you can get the R-12
> charge about right if you monitor the inlet and outlet pipe
> temperatures of the evaporator while the engine runs at fast idle
> (must be fast, and run the engine at least 10 minutes before charging)
> and you slowly (emphasis on "slowly") put in R-12 until the outlet is
> almost as cold as the inlet. Ideally they should be equal, but it's
> safer to undercharge than overcharge.
>
> > Where can I find the normal low-side, high-side pressure ranges?
>
> Any car repair manual that covers GM vehicles since they went to
> orfice tubes?