PeachParts Mercedes-Benz Forum - 1997 W202 C280 AC clicking noise

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1997 W202 C280 AC clicking noise

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.

Have you checked the pressures with a manifold set? It is possibly a low charge.

Thanks for the reply LarryBible. I have not checked that, I have yet to find a shop manual for this thing and have no idea how to go about it. Is there some sort of special tool required?