your belt and or tensioner is loose.the speed sensor in the compressor is kicking out the clutch.when you start the car hot make sure that the a/c is turned off completely,let the idle stabilise and then start the a/c.it should come on.

__________________
David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg