单项选择题
Coolant can be lost from a diesel engine jacket cooling waster system by leakage from（）
A.cylinder head cracks B.piping joints C.pump leaking D.all of the above
单项选择题 Ring groove inserts are occasionally used on aluminum alloy piston to（）
单项选择题 A sudden drop in diesel engine cylinder compression pressure can be caused by（）
单项选择题 Which of the following statements is correct for the design and installation of diesel engine cooling water systems?（）
