> wrote in message
ups.com...
> This is a 1990 Geo Metro. This car was previously converted to R134a.
> Recently I replaced the compressor and dryer. I did everything by the
> book. I flushed the system with isopropyl alcohol, replaced o-rings,
> evacuated, oiled it and held a vacuum for several hours. There were no
> leaks. I even purged it again with dry N2 and evacuated again.
>
> Book calls for 1.1 lb of refrigirent (this was for R-12, so I was ready
> to use only 1 lb of R134a). After putting in 1 lb of R134a, the
> pressure did not reach the specified values (200/25 psi on the high/low
> sides). I added some extra refrigirent, and then some more. The
> pressure was still low. I ended up putting in twice the required amount
> of refrigirent. But the pressure was still only 125/25 psi. I do not
> hear or see any obvious signs leaks. Even if there were a leak,
> wouldn't the pressure initially go up and then slowly come down? Where
> is all the extra refrigerent going? The air is blowing a little cool,
> but nowhere near where it should be. The high side tubes are hot, which
> is a good sign. The compressor is turning over fine, and there are not
> funny sounds. I am at a loss what to try next.
>
> Any suggestions are appreciated.
>

Sounds like your compressor isn't any good. Is the needle shaking or does
it hold steady? Overcharging the system would only make matters worse. Did
you happen to manually turn the compressor hub before letting the clutch
engage? As far as I understood, the amount of R134a compared to R12 should
be less. Something like 80% was it? Putting in 1 lb R134a compared to 1.1
lbs R12 is only 90%.