单项选择题
A.free entry of air to the crankcase
B.water entering the crankcase while engine wash-downs are being performed
C.excessive oil leakage during periods of increased blow-by
D.sub-cooling internal components
单项选择题 If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will （）
单项选择题 Lubricating systems for diesel engines are usually designed to initially provide lube oil to the engine （）
单项选择题 The expansion tank in a diesel engine closed freshwater cooling system is located at （）