Vehicle: North american market, 1995 855 GLT with 59K miles.

Noticed the AC compressor cylcing on and off about every 5 seconds
(during a check after replacing accessorty belt). I understand this
fast cycling is a very good indicator that the refrigerant level is
low -- I do still get some cool air, though. I'm thinking I would try
an AC re-charge before doing anything else (in the hope it would make
it through the summer) where anything else means the expensive evaporator
replacement.

I don't know much about AC or the correct questions to ask to make
sure the job is done right. A page at volvospeed.com says 1.6 lbs of
refrigerant is needed. Does this mean all existing refrigerant should
be removed (how else would you know how much to add -- is there an
AC dipstick?)? Would most garages just charge it up a "bit" or is it
more high-tech then that?

Thanks in advance.