单项选择题
You are inspecting the lower main precision bearings on a diesel engine.You observe that about half the thin Babbitt linings are of a milky white colourThis condition is caused by （）
A.large dirt particles in the oil supply B.insufficient lubricating oil and overheating C.normal wear D.water contamination of the lube oil
单项选择题 A substantial increase in crankcase pressure could be an indication of （）
单项选择题 Scuffed cylinder liner wearing surfaces in a diesel engines can result from （）
单项选择题 Exhaust pipes for separate diesel engines can be combined only when （）
