单项选择题
A.air binding of the engine cooling system
B.a cracked water cooled exhaust manifold
C.blockage in the heat exchanger
D.faulty operation of the thermostat
单项选择题 One result of operating a diesel engine at light load with excessively low cooling water temperature is a/an （）
单项选择题 The plunger in a jerk pump is rotated until the release port is uncoveredIf the port remains uncovered all of the time, which of the listed operations will occur?（）
单项选择题 If the compensating needle valve of a hydraulic governor is opened more than necessary the governor will （）