Cooling Systems Flashcards
Shrouding is used around a fan to:
a. Simply protect the fan blades
b. Increase fan efficiency
c. Reduce the noise of fan operation
d. Make it look neater
b. Increase fan efficiency
A collapsed radiator hose could be a sign that the:
a. Water pump is cavitating
b. Thermostat is opening too quickly
c. Vacuum valve is stuck closed
d. Head gasket is leaking
c. Vacuum valve is stuck closed
When the thermostat is closed, water is circulated through the engine water jacket by means of:
a. A bypass
b. The upper hose
c. The lower hose
d. A restrictor valve
a. A bypass
The reason that a viscous fan clutch uses silicon oil is that its viscosity [blank] as temperature increases.
a. Increases greatly
b. Decreases greatly
c. Stays comparably more stable
d. Does not change at all
a. Increases greatly
The purpose of the bimetal coil spring on the front of a viscous fan clutch is to:
a. Change the oil’s viscosity with temperature
b. Allow the fan to free wheel in hot weather
c. Control the entry of silicon oil to the fan clutch’s working chamber
d. None of the above
c. Control the entry of silicon oil to the fan clutch’s working chamber
The purpose of the radiator pressure cap is to pressurize the cooling system so that the system can be operated:
a. With no danger of radiator collapse
b. Safely at higher temperatures
c. Safely at higher speed
d. Without antifreeze
b. Safely at higher temperatures
The two valves in the pressure cap are the pressure relief valve and the:
a. Blow off valve
b. Vacuum valve
c. Radiator valve
d. Purge valve
b. Vacuum valve
The driving friction provided by a V-belt is on:
a. Both sides of the belt
b. The sides and bottom of the belt
c. The bottom of the belt only
d. The top and bottom of the belt
a. Both sides of the belt
Fan blades are sometimes arranged in an uneven fashion in order to:
a. Improve air circulation
b. Balance the unit
c. Reduce turbulence and noise
d. Equalize the weight distribution
c. Reduce turbulence and noise
How much of the heat energy in the fuel must be handled by the cooling system?
a. 1/4
b. 1/3
c. 1/2
d. 1/10
b. 1/3
Thermostats are usually installed between the:
a. Pump inlet and the radiator
b. Pump outlet and the water jacket
c. Water jacket and the radiator
d. Cylinder head and intake manifold
c. Water jacket and the radiator?
What is the boiling point of water with a 10lbs pressure cap?
a. 106 C (222 F)
b. 111 C (232 F)
c. 117 C (242 F)
d. 122 C (252 F)
c. 117 C (242 F)
Water pumps are usually [blank] type pumps.
a. Positive displacement
b. Centrifugal
c. Piston
d. Vane
b. Centrifugal
A pressurized cooling system not only raises the coolant boiling point, but also:
a. Prevents corrosion build up
b. Aids heat transfer
c. Increase the water pump efficiency
d. Both B and C
c. Increases the water pump efficiency
A closed cooling system is a standard pressurized cooling system the addition of a:
a. Special thermostat and radiator hoses
b. Special radiator cap and thermostat
c. Special radiator cap and coolant recovery tank
d. Locking radiator cap and sealed hose clamps
c. Special radiator cap and coolant recovery tank
The recommended antifreeze / water mixture for best overall cooling system performance is:
a. 20 / 80
b. 30 / 70
c. 50 / 50
d. 60 / 40
c. 50 / 50
The recommended type of antifreeze used for cooling systems is:
a. Ethylene glycol
b. Denatured alcohol
c. Tetra-ethyl lead
d. Methanol
a. Ethylene glycol
A tech states that a thermostat can only cause overheating at freeway speeds but that it can be left out of the engine with no ill effects.
a. True
b. False
b. False
The most likely cause of overheating at highway speeds is:
a. Thermostat stuck open
b. Electric fan not functional
c. Inadequate radiator core capacity
d. Incorrect antifreeze concentration
c. Inadequate radiator core capacity
What is the most likely cause of an engine overheating in city stop and go traffic?
a. Thermostat stuck open
b. Electric fan not functional
c. Inadequate radiator core capacity
d. Incorrect antifreeze concentration
b. Electric fan not functional
Continuous bubbling observed at the radiator filler that stops when the engine is shut off could be a sign that:
a. The head gasket is leaking
b. The coolant is boiling
c. There is a localized hot spot in the cooling system
d. Any of the above
a. The head gasket is leaking
Continuous bubbling observed at the radiator filler that continues after the engine is shut off could be a sign that:
a. The head gasket is leaking
b. The coolant is boiling
c. There is a localized hot spot in the cooling system
d. Any of the above
b. The coolant is boiling
The reason that the upper radiator hose fails more often than the lower one is that it:
a. Is more subject to chafing by clumsy mechanics
b. Is easily pinched between the hood and fan shroud
c. Operates at a much hotter temperature
d. None of the above
c. Operates at a much hotter temperature
Electric fans are used because they:
a. Cool the engine more efficiently at low speed
b. Help the engine to warm up faster
c. Cost less to manufacture
d. Require less power to operate
a. Cool the engine more efficiently at low speed
A cooling system has been filled with 100% pure ethylene glycol. This could cause:
a. The engine to overheat
b. The boiling point of the coolant to be raised
c. Rapid and severe corrosion of aluminum parts
d. No harmful effects
a. The engine to overheat
Cooling systems are pressurized to:
a. Prevent the coolant from rusting the engine metal
b. Make water pump lubrication unnecessary
c. Raise the coolant’s boiling point
d. None of the above
c. Raise the coolant’s boiling point
Which of the following is NOT a part of the radiator?
a. Tubes
b. Core plugs
c. Fins
d. Tanks
b. Core plugs
A cross flow radiator:
a. Has a tank at either side of the core
b. Operates in the same way as a down flow radiator
c. Allows a lower car hood line
d. All of the above
d. All of the above
The curved chamber of a water pump is called the:
a. Impeller
b. Pulley
c. Scroll
d. Any of the above
c. Scroll
Water pumps must turn [blank] to be efficient.
a. Fast
b. Clockwise
c. Counterclockwise
d. None of the above
a. Fast
A belt driven radiator fan:
a. May cause more air flow at idle or low vehicle speed
b. May waste engine power at high vehicle speed
c. Both A and B
d. Neither A nor B
c. Both A and B
At low engine speeds, a variable pitch fan blade is:
a. Flattened
b. Sharply angled
c. Pulling less air
d. None of the above
b. Sharply angled
When you work on an engine that has an electric radiator fan, you should [blank] before you get near the fan.
a. Install a shroud
b. Disconnect the battery positive cable
c. Bring the engine to its normal operating temperature
d. Disconnect the battery ground cable
d. Disconnect the battery ground cable
Late model thermostats are operated by:
a. A thermo-siphon
b. A wax pellet
c. A bimetal temperature sensor
d. Any of the above
b. A was pellet
What is stamped on the outside of a replacement thermostat?
a. The engine displacement
b. Wax
c. The opening temperature
d. The direction of installation
c. The opening temperature
Radiator hoses can be:
a. Moulded in a specific shape
b. Ribbed, with flexible lengths
c. Reinforced with a wire coil
d. Any of the above
d. Any of the above
A radiator cap contains:
a. A pressure valve
b. A vacuum valve
c. Both A and B
d. Neither A nor B
c. Both A and B
Coolant recovery systems:
a. Increase cooling system efficiency
b. Use pressure caps that don’t vent to the atmosphere
c. Always maintains a full cooling system
d. All of the above
d. All of the above
The strength of the antifreeze solution is checked with a / an:
a. Ammeter
b. Hydrometer
c. Voltmeter
d. Dynameter
b. Hydrometer
Electric radiator fans run:
a. At all times
b. When the cooling system reaches a preset temperature
c. When ever the air conditioner is used
d. B and C are correct
d. B and C are correct
About two-thirds of the heat energy from combustion is converted into mechanical energy.
a. True
b. False
b. False
Earlier engines tend to run colder than the late model engines.
a. True
b. False
a. True
Most engines use a liquid coolant to transfer heat from the atmosphere to the engine metal.
a. True
b. False
b. False
The thermostat controls coolant circulation between the water pump and the cylinder block.
a. True
b. False
b. False
The cooling system is pressurized to increase water pump efficiency and to raise the coolant’s boiling point.
a. True
b. False
a. True
For every 1psi increase in cooling system pressure, the coolant’s boiling raises by about 3F (2C)
a. True
b. False
a. True
Having more than 75% ethylene-glycol in a coolant mixture will raise rather than lower the freezing point.
a. True
b. False
a. True
Core, or freeze plugs protect an engine from the damage which can occur if the coolant mixture should freeze.
a. True
b. False
b. False
Other than flow direction, there is no operational differences between down flow and cross flow radiators.
a. True
b. False
a. True
Flexible fan blades are designed to conserve engine power.
a. True
b. False
a. True
When the fluid drive fan is hot, there is very little silicone present in the drive side.
a. True
b. False
b. False
Electric radiator fans cannot run when the vehicle’s ignition is off.
a. True
b. False
b. False
Wax-actuated thermostats do not operate reliably under varying cooling system pressures.
a. True
b. False
b. False
The thermostat is mounted in the top or side of the radiator tank.
a. True
b. False
b. False
The radiator cap vacuum valve allows antifreeze to return to the radiator as the coolant cools.
a. True
b. False
a. True
