350 SDL Injector Life Span Is?
 

At how many miles would these injectors typically be replaced as a maintenance item? Does MB have any criteria for this?

Thank you?

Essentially when they won't work properly. They've been known to run 250,000 miles without replacement on well maintained vehicles.

What usually happens is that either the opening pressure drops too low or the orifice wears to the point it won't spray properly, giving a solid stream or off-center mist. Can only be determined by removing and testing. Both conditions cause excessive knock.

Peter