In a normally operating diesel engine, the main cause of lubricating oil contamination in the crankcase is a result of the （）.

[单选题]In an operating diesel engine, which of the following conditions is an indication of a leaking air starting valve?A．Noise coming from that air starting valveB．Continuous operation of the starting air compressorC．Zero air pressure in the air starting

[单选题]A diesel engine is operating with excessively high exhaust temperatures at all cylindersTo correct this condition, you should FIRST （）.A . reduce the engine loadB . increase the cooling water flowC . increase the lube oil pressureD . adjust the fuel

[单选题]Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause （）.A . the formation of sulfuric acidB . a decrease in lube oil viscosityC . a decrease in co

[单选题]How should you warm up a diesel engine that has not been run for some time? （）A . Run it at minimum speed for a period of timeB . Run it at half speed for a period of timeC . Bring it to top speed immediatelyD . Inject ether into the air intake

[单选题]The operating diesel generators will have their exhaust temperatures, cooling water and lubricating oil temperatures and pressures （） in much the same way as for the main engine.A . to be keptB . loggedC . changedD . has remained

[单选题]_____ the engines, the diesel engine is ____ used engine on boardA．Between / more commonlyB．Among / the most commonlyC．Between / not more commonlyD．Among / not the most commonly

[单选题]The heart of the diesel engine is the （） where the fuel is burnt and the power developed.A . crankcaseB . cylinderC . scavenge boxD . pisto

[单选题]The diesel engine is a type of （）.A . turbine engineB . gas turbineC . steam engineD . internal combustion engine

[单选题]D．iesel engine blow-by is the leakage of combustion gases past the( ).A．oil rings onlyB．compression and scraper ringsC．cylinder liner sealingD．cylinder liner ring grooves

[单选题]F．or a continuous operation diesel engine, a duplex filter unit would be the best arrangement becauseA．changing filter elements would not interrupt engine operationB．filtering occurs twice in each pass of oil through the systemC．clogging will not occ