单项选择题
Which of the following conditions can cause below normal air pressure in the intake manifold of a turbocharged diesel engine?（）
A.Excessive piston blow-by to the manifold B.Insufficient cooling water flow C.Accumulated water in the air boxes D.Clogged air intake filters
单项选择题 If sludge accumulates on the underside of a diesel engine piston, it will（）
单项选择题 Which condition indicates the air side fouling of an after-cooler on a turbocharged diesel engine?（）
单项选择题 Black areas on the sealing surfaces of piston rings indicate（）
