In the closed cooling system, the water （）.

In a diesel engine closed freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the __.

A.suction pressure regulator

B.thermostatic bypass valve

C.sea water temperature

D.water level in the expansion tank

Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can ______.

A.increase power output

B.decrease lube oil viscosity

C.eliminate fuel knock

D.cause sulfuric acid formation

What is head tank in the closed cooling water system used for?

A.for the release of air from the cooling water

B.providing expansion room for heated cooling water

C.a place for implementing water and water treatment agent

D.all of the above

High diesel engine cooling water temperatures can be caused by ______.

A.air in the cooling system

B.an overhauled water pump

C.correct amount of coolant

D.no air in the cooling system

Why is it necessary to have routine testing of the cooling water?

A.To ensure that the proper residuals of treatment chemicals, as specified, are maintained all time

B.To trace leakage in the cooling water system

C.It is not necessary

D.To detect the presence of contaminants in the water that may be injurious to the cooling system

If the coolant temperature of a closed cooling water system for a diesel enginegradually increases, the trouble usually is( ).

A.a broken shaft on the freshwater pump

B.an excessive accumulation of scale in the heat exchanger

C.an incorrect thermostatic element operating range

D.lube oil in the cooling water