The cooling water of the diesel engine should be treated with chemical, because it contains .

A．alkali

B．acidity

C．salinity

D．impurity

[单选题]In a diesel engine cooling water system, a pH of 60 indicates a/an （）.A . slightly acidic conditionB . slightly alkaline conditionC . overtreatment of waterD . neutral condition of water

[单选题]A diesel engine cooling water system with a pH factor of 30 indicates a condition of （）.A . slight acidityB . slight alkalinityC . excessive alkalinityD . excessive acidity

[单选题]High diesel engine cooling water temperatures can be caused by （）.A . a worn water pumpB . not enough coolantC . air in the cooling systemD . all of the above

[单选题]Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits may cause （）.A . low compression pressureB . increased piston wearC . increased cylinder lube oil consumptionD . poor contact between compression rings and l

[单选题]For diesel engine piston cooling, lubricating oil can be supplied to the pistons by a/an （）.A . oil sprayB . oil bathC . oil control ringsD . drilled passage through the camshaft

[单选题]The pH value of water in a diesel engine closed cooling water system should be maintained between （）.A . 60 to75B . 80 to 95C . 100 to 115D . 120 to 135

[单选题]Diesel engine jacket water is used in the distillation process as the （）.A . coolant for the distillateB . coolant for the brine coolerC . means of heating the feedwaterD . primary means of producing a vacuum within the distiller

[单选题]Immediately after any diesel engine is started, the engineer should check the （）A . crankcase pressureB . lube oil pressureC . saltwater pressureD . exhaust temperature

[单选题]There is （） in any water cooling system for a diesel engine allowing for expansion and water make-up in the system as well as air vent and chemicals addition.A . a setting tankB . a service tankC . a head tankD . an expansion joint

[单选题]The cooling water temperature （） over a period of 8 hours, and then shut down.A . should be gradually increasedB . should be gradually reducedC . should be constantly keptD . should be varied up and dow