350 SDL ... 190K miles

Started noticing noise on start up ... sort of a "rrrr ... rrrr ... rrrr ... rrrr" synced with the engine speed - goes away above 1000-1200 rpm. Kept looking for the noise - thought might have been the vacuum pump ...

Noise changes when I engage the a/c compressor - but, doesn't go away.

Today I carefully examined the belt while the engine was stopped - noticed the belt was beginning to shred along the inside edge (closest to the engine side) - the edge was damaged with a sliver missing from the inside edge along an area about 12 inches in length ...

I had noticed this same damage on a previous belt - since then I have replaced the belt, the tensioner, tensioner pulley, and shock absorber. In fact, I have replaced the portions of the tensioner four separate times over the last seven years.

I then carefully examined the tensioner assembly - I don't note any of the excessive movements that were characteristic of previous issues with the tensioner.

So, ruling out the tensioner itself (admittedly a simple, but poorly designed mechanism on this engine), what could be causing this - and, is the belt damage likely related to the noise?

I examined the alternator, a/c compressor, belt routing, etc ... just can't see anything that looks like something is incorrectly installed, mounted off center, or unaligned, not square with belt, etc ...

Anyone have any suggestions? I can continue to replace the belt, but it seems like this is indicative of other issues ...

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg