[oldcomputerguy]

Telling someone to add 3 pounds of r-134a to a car for which you have no idea of the make/model is irresponsible. The system is either charged to exact weight which is posted on the car or slightly less if converting. In the conversion process the system is often charged by pressure at 2x ambient temperature plus 40 psi for r-12 or plus 60 pounds for r-134a. 48 oz of r-134a would probably blow the safety plug on the compressor assuming it had one.....or it would blow the compressor.