Hi folks,

My brother just picked up a W202 C280 of 1997 vintage that is in beautiful shape, L6 M104 2.8l, ~120k, however it makes a clicking noise when the AC or heat is on. AC blows cold, heat works fine, but this clicking is kind of irritating. It goes away above about 1700rpm. Is the AC clutch on the way out? It sounds like its coming from that vicinity. What is the mode of failure of these things? Will it throw the serpentine belt if it fails? That could yield an overheat which would be very bad.

EDIT: Although the context implies it, I guess I should state explicitly that the click interval is inversely dependent on engine rotational speed.

__________________
99 E300 Turbodiesel 100k