I have hunted thru the Haynes and FSM, along with countless other places, and still cannot find out one simple answer.
How much refrigerant does the A/C hold?
I know this is usually listed on a label somewhere under the hood, but my car has dealer added A/C, and the label was paper. No longer legible. I know dealer A/C systems can vary from factory systems in the amount needed for a full charge, but I need an approximate figure, so I can calculate the approx amount of R134 to fill my system. It cools pretty fair with 20oz of R134, but with these 100+ days, it could use a bit more help. I know it is not quite at capacity, but without a rough idea of the total needed, I don't want to accidentally overfill the system.

 

Going by memory I believe that for R12 it was between 28-32 OZ of freon. Then approx 80% of that for R134A. Unless someone chimes in, the only 2 places I know of to get this info is either the sticker on the car or the FSM.

 

That sounds about right doc. I have hunted thru the FSM, and cannot find any numbers for the A/C. Not saying it's not there, somewhere, just not where I would think it would be.
According to the info I have, retrofitting an R12 system to R134A requires approx 80-85% of the original refrigerant charge. That relates to between 22 and 27oz R134A.