Cooling （） the engine metals retain th

1、（）, the metal expands.

（）, the metal expands.AHeatsBHeatingCTo heatDHeated

2、In a diesel engine cooling water syste

In a diesel engine cooling water system, a pH of 60 indicates a/an （）.Aslightly acidic conditionBslightly alkaline conditionCovertreatment of waterDneutral condition of water

3、If the engine （） for a long period, th

If the engine （） for a long period, there will be a danger of frost.Amust to stand inoperativeBhas to stand inoperativeCmust be stood idleDwill stand idle

4、The cooling water of the diesel engine

The cooling water of the diesel engine should be treated, because it has（）Aalkale scenceBacidityCsalinityDimpurity

5、Cooling of engine is achieved by circu

Cooling of engine is achieved by circulation a cooling liquid around internal passages within the （）.AboilerBheaterCengineDcooler

6、Improper cooling of a diesel engine cy

Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits may cause （）.Alow compression pressureBincreased piston wearCincreased cylinder lube oil consumptionDpoor contact between compression rings and liner