119 can Oiler tubes how to tell bad ones?
 

I’m going to be diving in to a 97 S500 with a ticking lifter issue. It’s a car I don’t think is worth replacing all the tubes as a shot gun approach since the tubes are nearly $25/each, times 8 that adds up. How can you tell which ones are bad? Do they crack or clog or what?

A small glued in plug pops out , therby lowering oil flow and pressure to the lifter , look a the oiler tube you will see a hole where the plug once was , and don't bother trying to fing the piece its down in the engine , no harm as pickup tube has a screen