Question 380General Subjects - 1st Asst/Chief

The correct answer is B) Piston ring or cylinder liner wear. High iron levels in used diesel engine crankcase lubricating oil indicate increased wear on the piston rings or cylinder liners. This is because as the piston rings and cylinder liners wear, iron particles from these components get released into the lubricating oil. The other answer choices are incorrect because they do not directly correspond to the elevated iron levels. Camshaft bearing wear (A), rocker arm or piston pin bushing wear (C), and main bearing or crank pin bearing wear (D) would not necessarily result in increased iron content in the lubricating oil.