Chain should be replaced when it has 8 degrees of stretch (or more if you just got the car). Not a milage kinda thing, you have to look.

Jim:

Fatigue failure of the surface, probably due to lack of proper lubrication. I see all the time in the peristaltic pumps at work. They have a pair of rails between the pressure rollers and the platen that presses the tygon tubing down, and they start to flake off bits when they get old and/or someone doesn't oil them enough. The metal flakes and rough surface then rapidly eat away at the rollers.

Not pretty!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!