Which valve do I add freon to upper or lower? on 1999 Cadillac Catera

Need to add freon . There are two ports, one on top nearer passenger Compartment and one lower nearer to radiator. Which do I use.

by in North Palm Beach, FL on March 27, 2011
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1 answer 1 comment
ANSWER by , March 27, 2011
I would not add any refrigerant if you are not familiar with a/c systems, take to a shop with the correct special equipment to do the job correctly, you can't just FIX a/c by JUST adding refrigerant.
COMMENT by , July 23, 2011
Well, freon can certainly be added if the system is low and fix the cooling problem if that's what the problem is.