1. clutch sounds like its okay, something is cutting power to the clutch

I know some of the newer systems like yours have a sensor somewhere which will cut off the compressor if it detects that the compressor is slipping on the belt. Could be a possibility.

It could also be shutting down due to incorrect system pressures, cause by to much or to little freon, a expansion valve that is acting up, fans on condenser not running causing pressures to go up...

You need to put gauges on the system and monitor pressure until the system starts to show problems like you are explaining.

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg