OT: 1990 Mercedes Benz 300E, Belt Noise?

[Tiger]

Belt would be my primary guess... but at high mileage due to age, I would also say the idler belt pulley (bearing inside) are shot too... along with his belt adjuster shock... About $100 will cover everything.

He has a "nut" to tighten or loosen the belt tensioner pulley... once he loosen that, he can work on everything else with ease. It would be better to move the fan along with the shroud to get to everything easily.

[Jean@MtMiguel]

Belt would be my primary guess... but at high mileage due to age, I would also say the idler belt pulley (bearing inside) are shot too... along with his belt adjuster shock... About $100 will cover everything.

He has a "nut" to tighten or loosen the belt tensioner pulley... once he loosen that, he can work on everything else with ease. It would be better to move the fan along with the shroud to get to everything easily.

Serpentine belt along with a replacement of the tensioner as Tiger stated will be a good cure, I have an '86 300E with the same engine configuration, the difference of the '90 will be the location of the AC compressor that it is sitting on top of the alternator, easy fix with Allen wrench, NOTE: before disassembly draw location of the pulleys/serpentine belt location. Also DO NOT USE WD40 on belts/ use candle as a lubing agent/ will not cause the belt to slip.

[winfred]

yea if the belts slip on a benz it will screw with the ac and shut it down when the motion sensor on the compressor detects slip