USCG Diesels: Coolant, Cooling
Systems, Expansion Tanks Questions
and Answers 100% Solved
High diesel engine cooling water temperatures can be caused by ______.
a) air in the cooling system
b) an open thermostat
c) maintaining only 1/2 an expansion tank level
d) excessive cooling water pump pressures - answer1. A
According to the illustration, if water is ejected from an open indicator cock when the
engine is rotated by the turning motor, a leak or crack may have developed at the
______. See illustration MO-0032.
a) injector seating surface
b) valve seat insert
c) upper portion of the cylinder liner
d) all of the above - answer2. D
The operation of the lube oil cooler, shown in the illustration as item #4, will be
characterized by which of the following statements? See illustration MO-0111.
a) The temperature of the sea water entering the cooler will be higher when operating
with the distiller on line.
b) The temperature of the lube oil entering the cooler will decrease whenever the the
distiller is on line.
c) The pressure of the sea water to the lube oil cooler will increase with the distiller on
line.
d) The pressure of the lube oil to the cooler will increase whenever the distiller is on line.
- answer3.A
Cooling water pumps driven by direct reversing diesel engines are usually of the straight
impeller vane type pump with a concentric housing to ______.
a) provide equal water flow capacity when the engine is running either ahead or astern
b) provide the greatest pump efficiency when running ahead
c) prevent pump clogging from marine growth
d) prevent cavitation at the pump outlet - answer4.A
Telescopic pipes which are attached to water cooled pistons of large slow-speed main
propulsion diesel engines are designed to ______.
a) overcome excessive crankcase pressure
b) prevent excessive lube oil temperature
, c) allow piston cooling water to efficiently enter the piston despite its reciprocating piston
motion without contaminating the engine lube oil
d) prevent contamination of the cylinder cooling water with engine lube oil - answer5.C
Why do most temperature control valves in diesel engine closed freshwater cooling
systems bypass the flow of jacket water around the cooler instead of around the
engine?
a) Changing the rate of flow in the jackets could cause localized hot spots.
b) Emergency hand control would not be possible if water flow through the jackets were
controlled.
c) Excessive cooling would take place in the heat exchangers at high loads.
d) Excessive cavitation erosion would take place in the coolers. - answer6.A
The operation of the lube oil cooler, shown in the illustration as item #4, will be
characterized by which of the following statements? See illustration MO-0111.
a) The temperature of the sea water entering the cooler will be higher when operating
with the distiller.
b) The temperature of the lube oil entering the cooler will be lower at higher engine
speeds.
c) The pressure of the sea water to the lube oil cooler will be higher when the distiller is
on line.
d) The pressure of the lube oil to the cooler will be higher when the distiller is on the
line. - answer7.A
The cooling water pump driven by a direct reversing diesel engine is usually of the
straight impeller vane type with a concentric housing to ______.
a) allow the pump to turn in either direction
b) provide equal pump efficiency turning in either direction
c) minimize pump clogging from marine growth
d) prevent cavitation at the pump outlet - answer8.B
Which precaution must be taken when securing a diesel engine if an electric jacket
water heater is installed in the engine block?
a) The coolant temperature must always be maintained at 180°F.
b) The thermostatic bypass valves must be manually opened before the engine is
started.
c) The pressure cap must be removed while the engine is secured.
d) Electrical power to the heater must be secured if the cooling system is to be drained.
- answer9.D
According to 46 CFR Part 56, isolation valves used in keel cooler installations may be
constructed of ______.
a) bronze
b) copper
c) high temperature plastic
d) aluminum - answer10.A
Systems, Expansion Tanks Questions
and Answers 100% Solved
High diesel engine cooling water temperatures can be caused by ______.
a) air in the cooling system
b) an open thermostat
c) maintaining only 1/2 an expansion tank level
d) excessive cooling water pump pressures - answer1. A
According to the illustration, if water is ejected from an open indicator cock when the
engine is rotated by the turning motor, a leak or crack may have developed at the
______. See illustration MO-0032.
a) injector seating surface
b) valve seat insert
c) upper portion of the cylinder liner
d) all of the above - answer2. D
The operation of the lube oil cooler, shown in the illustration as item #4, will be
characterized by which of the following statements? See illustration MO-0111.
a) The temperature of the sea water entering the cooler will be higher when operating
with the distiller on line.
b) The temperature of the lube oil entering the cooler will decrease whenever the the
distiller is on line.
c) The pressure of the sea water to the lube oil cooler will increase with the distiller on
line.
d) The pressure of the lube oil to the cooler will increase whenever the distiller is on line.
- answer3.A
Cooling water pumps driven by direct reversing diesel engines are usually of the straight
impeller vane type pump with a concentric housing to ______.
a) provide equal water flow capacity when the engine is running either ahead or astern
b) provide the greatest pump efficiency when running ahead
c) prevent pump clogging from marine growth
d) prevent cavitation at the pump outlet - answer4.A
Telescopic pipes which are attached to water cooled pistons of large slow-speed main
propulsion diesel engines are designed to ______.
a) overcome excessive crankcase pressure
b) prevent excessive lube oil temperature
, c) allow piston cooling water to efficiently enter the piston despite its reciprocating piston
motion without contaminating the engine lube oil
d) prevent contamination of the cylinder cooling water with engine lube oil - answer5.C
Why do most temperature control valves in diesel engine closed freshwater cooling
systems bypass the flow of jacket water around the cooler instead of around the
engine?
a) Changing the rate of flow in the jackets could cause localized hot spots.
b) Emergency hand control would not be possible if water flow through the jackets were
controlled.
c) Excessive cooling would take place in the heat exchangers at high loads.
d) Excessive cavitation erosion would take place in the coolers. - answer6.A
The operation of the lube oil cooler, shown in the illustration as item #4, will be
characterized by which of the following statements? See illustration MO-0111.
a) The temperature of the sea water entering the cooler will be higher when operating
with the distiller.
b) The temperature of the lube oil entering the cooler will be lower at higher engine
speeds.
c) The pressure of the sea water to the lube oil cooler will be higher when the distiller is
on line.
d) The pressure of the lube oil to the cooler will be higher when the distiller is on the
line. - answer7.A
The cooling water pump driven by a direct reversing diesel engine is usually of the
straight impeller vane type with a concentric housing to ______.
a) allow the pump to turn in either direction
b) provide equal pump efficiency turning in either direction
c) minimize pump clogging from marine growth
d) prevent cavitation at the pump outlet - answer8.B
Which precaution must be taken when securing a diesel engine if an electric jacket
water heater is installed in the engine block?
a) The coolant temperature must always be maintained at 180°F.
b) The thermostatic bypass valves must be manually opened before the engine is
started.
c) The pressure cap must be removed while the engine is secured.
d) Electrical power to the heater must be secured if the cooling system is to be drained.
- answer9.D
According to 46 CFR Part 56, isolation valves used in keel cooler installations may be
constructed of ______.
a) bronze
b) copper
c) high temperature plastic
d) aluminum - answer10.A
