cgshawaii

G'day all. My wife's '98 C280, M112 V6, 76,000 miles, has a loud metallic whir coming from the engine. I just changed out, for the second time, the water pump and fan clutch, since the pump shaft had a little wobble. It had not gotten to the point of leaking... yet, but now it's new and that's off the table. The serpentine tensioner and idler pulleys spin very freely and without noise when not loaded.

The noise is present with the engine warm or cold and presents like a something spinning in a bearing that is losing its cool. The noise is quite noticeable standing next to the car, but thanks Messrs Benz und Daimler, barely audible inside the car as long as the windows are up.

Years before we bought it, the entire engine was re-sealed and trans removed and flushed. This after the car was traded in to the BMW dealer, who knowing of the problem sold it without disclosing to the buyer from whom we later got the car. I've had to replace a conductor plate and one shift solenoid since - $1200 at a local independent, the one time I couldn't solve the issues myself.

I have thought to temporarily take off the serpentine belt and listen for the noise. I know this disables the water pump and the engine will heat, but for at most a couple minutes, probably less, it will be okay.

Also open to suggestions from the group; TIA and have a great weekend!