135. With a machinery lubricating oil analysis program, it is important to monitor trends over time. What would be indicated by a sudden increase in metallic content of a recent sample of used diesel engine crankcase lubricating oil?

A sudden increase in metallic content in used lubricating oil indicates accelerated wear of engine parts. Metallic content in oil analysis reflects wear metals originating from engine components; a sudden spike signifies abnormal wear, not dilution, additive depletion, or coolant contamination.