Tinkle, Tinkle, Tinkle
 

I have a 1989 260E I am in the process of refurbishing. 110,000 miles. The car has developed a "tinkling" sound from the engine compartment. I have also noticed that the serpentine belt is wobbling. From reading the posts here, it appears to be the water pump on its way out. It is not leaking water. Green coolant was put in by the prior owner and has probably been there for a couple of years. Does this sound familiar to anyone?

Could also be the idler pulley bearing.
Gilly

Isn't there also a fan pulley bearing separate from the water pump pulley in an M103?

Sixto
93 300SD

Yup, good point, could be that too. The idler pulley bolts to the small arm on the fan bearing bracket, and that's about as common to make noise as the idler pulley. I'd describe the noise as a chirping noise, but they can sound different and be described differently.
Gilly

Maybe the fan is scratching the radiator?

Sixto
93 300SD