Shredded Serpentine Belt, 95 E320

[TROVERMAN]

Within less than a year and 10k miles after an OEM german serpentine drive belt was put on the car (by a mercedes master mechanic), it snapped or shredded. The person driving the car at the time did not realize the belt had let go and continued driving for about 10-12 more miles, suspected a failed alternator (as the light was on). When I diagnosed the shredded belt, the car was transported home by flatbed. The belt was in a hundred strings, all wound in and behind many of the pulleys. I removed as many as I could see, all the pulleys spin freely (except crank, of course) Because the car was driven with no water pump running for those 10 miles or so, there was no coolant in the overflow tank, so it must have been hot. The saving grace for the engine was 1., temps in the single digits; 2., secondary water pump circulating coolant a little plus twin electric fans operating at full thrust; 3., the m104 is a tough engine.

After recharging battery, adding coolant, and a new belt (this time a goodyear gatorback), the engine started and seemed to run fine. There is more belt stuck behind the fan viscous drive, so the fan runs fully engaged all the time, resulting in engine roar and slow warming up. Other than that, the car seems fine.

The question is, why did it break and shred?

The first thing I noticed about 2 weeks before the problem was little puddles of oil forming under the car. Keep in mind the head gasket had been done at the same time we got the new serpentine and that had cured oil leakage. The oil leaking had gotten all over the pulleys and the drive belt was wet, something that had not happened during the headgasket oil leak. Although oily and wet, the belt seemed fine and all accessories seemed to be working fine. I diagnosed the leak as from the rear suspension fluid, either the hoses going from the tank of fluid to the pump or from the pump itself. The fluid level in the reservoir went to a low level and stopped leaking.

Upon inspecting the vehicle the day before the belt shredded, I cleaned up the wet hoses from and to the power steering / rear suspension pump, tightened a clamp, and added more suspension fluid (not to the correct level in case it just leaked out again, but quite a bit.) I ran the engine, and the fluid did not seem to be leaking.

I then noticed something flailing on the engine side of the serpentine drive belt. Shutting off the engine, I noticed very light and intermittent shredding on the engine side of the belt. The shredding was about 1mm of belt was peeling, and I broke it off. I noticed one of the power steering lines seemed very close to the belt and this seemed to be the cause of the light shred. I securely relocated the hose, and since the belt had just the slightest damage I deemed it fine to run. Of course, the belt shredded the next day!

Could the hydraulic suspension fluid on the belt and pulleys have caused the belt to slip off and break / shred?

Before replacing the belt, I felt all of the pulleys and they all seemed smooth with a couple having the very slightest of imperfections. After three days of very cautious driving, it seems fine.

Any thoughts on why this might have happened would be appreciated. Also, how do I remove the fan / pulley, so I can get the rest of the belt fragments out?

Finally, the air pump: the wiring going into the clutch was hit by the flailing belt and is now bare. There are only two wires going in, a red and black. About 1" of wiring is exposed. I taped off as best I could, but the insulation is gone even as it goes behind the metal pulley. Nothing seems to be shorting but not so sure the pump is working anymore either. Any way to remove the pulley / clutch and get at the wiring easily?

Thanks in advance.