[W126 Coupe] Another AC Problem

[Tom Oelsner]

A couple of weeks ago, with the help of a number of people here providing
information, I got my AC running again.  I replaced the O rings behind the
compressor and evacuated it (held pressure perfectly), replaced a seized AC
idler pulley and recharged the system using Duracool.  The system has been
running perfectly, until today.  I have put about a 1,000 miles on the car
in the last 2 weeks, about 500 in the last 2 days.  Today, I started hearing
sounds as if bearings are going (or almost like a belt is slipping) but the
AC is still blowing very cold.  I am not convinced that it is a slipping
belt because it only happens when the AC is turned on.  Has anybody
experienced this before or have any suggestions for isolating and
identifying the problem?

Tom Oelsner
560SEC