A/C Not Cold - 94 Buick Regal 3.8

I have a 94 Regal with 94,000 miles. The air blows strong, but it does not get cold. How can I find if the problem is the compressor, evaporator, condensor, or refrigerant leak? If it is a leak, what type & brand of sealent and refrigerant is best for this age car?
Thanks,

Dan

The first thing you need is a set of A/C guages. You need to check both hi side and low side pressures, then check a chart that compensates for both outside temp and humidity. These readings will tell you if you have insufficient charge, a blockage, etc...

65% of A/C system failures in my database are due to loss of refrigerant due to a leak- most likely the compressor shaft seal and/or o-ring joints on your H-6 compressor, so you can draw your own conclusions..look for oil slinging at front of compressor-- is radiator hose wet? is compressor wet, oily. grimey

I strongly advise not to use sealers- they don't work and will contaminate your system...