Is the compressor about to go out?

[Benzadmiral]

Hi, all,

I've had my '97 C230 for about 6 weeks now, and am familiar with its normal sounds and lack of same. The A/C has been blowing nice and cold in our New Orleans heat. Yesterday afternoon, however, as I was sitting at a stop light, the engine began to vibrate -- pretty gently, all things considered, but I could feel it in the wheel and shift knob, where even with air on high the idle is usually glass-smooth. Also I can hear a new puttering or purring noise from the engine bay, audible even with the windows up (and quite audible with them down as I drive by a wall or through a tunnel). The A/C remains cold, and seems to perform perfectly.

When I turn off the A/C, the vibration and noise disappear, only to return when I restart the A/C. The car does not stall or hesitate with the air on or off. Temp gauge sits at ~87 C., and the tach is steady at 550-600 or so.

Am I about to have to buy a new compressor? Is it possible that I just need a new V-belt? Or is this noise and vibration normal (if so, why would it only appear now)?

Any advice would be appreciated!