Replace timing chains/guides every 100,000 miles on Mercedes-Benz 420SEL

Problem Description and Possible Solution
The timing chain and timing chain guides wear; they should be replaced every 100,000 miles.
Problem Data
RepairPal Verified
Average mileage: 192,500 (187,000–198,000)
2 model years affected: 1990, 1991
4 people reported this problem
Viewing 1 - 2 of 2 problem details
Replace timing chain every 150,000 miles
Mechanic stated that timing chained slipped and caused severe damage to car engine.