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單項(xiàng)選擇題

Small crack in the crankshaft bearing surface of a diesel engine are an indication of（）

A.corrosion fretting
B.insufficient lubrication
C.abnormal wear
D.fatigue failure

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單項(xiàng)選擇題

Fuel oil day tanks for diesel engines must be checked and cleaned and cleaned at regular intervals in order to remove（）

A.sludge
B.water
C.micro-organism growth
D.all of the above

單項(xiàng)選擇題

Excessively worn, or polished ends on a diesel engine valve spring, indicate（）

A.burned exhaust valves
B.excessive spring compression
C.spring surge
D.worn valve seats

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