83 240D with AC Compressor on shakes like crazy at idle
 

My 83 240D with AC Compressor on shakes like crazy at idle. It sounds as if the compressor is loose or a cheapo ( I got it from Pep Boys) but it really does pump cold air! The compressor is on tight, of course. Its just that when I'm at a stop light, it sounds as if something will fall out of the engine compartment.
I use the same compressor on my 85 300D and its very quiet!!


83 240D with AC Compressor on shakes like crazy at idle

Does increasing the idle speed with the little knob on the dash help smooth the idle shake out? If so, I would suspect your engine mounts of being tired. They stiffen up and the natural frequency increases. The a/c load will bring the idle down a little and then the frequency offset between the natural frequency of the mounts and the forcing function of the engine get a little too close. If the unit is not loose and it works fine on your other car, doubt the a/c compressor will cause the engine to shake. Good luck, Jim