Go to this address:
http://www.mbca.org/MBCA_parts_wear_out.htm

It offers general guidelines on Mercedes parts.

__________________
Ben

The MBs:
1976 300D (W115) - 330K and still going (sort of)
1991 300D 2.5 Turbo - Sold at 221K
1983 280SEL - Sold at 206K
1981 300SD - Sold at 232K