5.3 Exercises for Unit 5
1. What percentage of engine heat is dissipated through the cooling,
lubricating, and fuel systems?
- A. Between 10% to 15%
- B. Between 20% to 25%
- C. Between 30% to 35%
- D. Between 40% to 45%
2. Why are cylinders on an air-cooled engine mounted independently?
- A. To reduce engine weight
- B. To expose more surface area to the cooling air
- C. To eliminate the need for cooling system maintenance
- D. To provide easy access to the crankcase
3. When inspecting an air-cooled engine, you notice a crack in one of the
cooling fins extending into the combustion area. What action is required?
- A. Replace the engine.
- B. Replace the cylinder barrel.
- C. Weld the cooling fin.
- D. Nothing, this will not affect the cooling.
4. What action is created during the downward flow of the coolant through the
- A. Thermosiphon
- B. Thermoexpansion
- C. Thermoflow
- D. Thermocooling
5. How do radiator fins contribute to cooling system efficiency?
- A. They hold the tubes in a position that allows maximum contact with the air
- B. They increase heat dissipation by enlarging the surface area exposed to the
- C. They increase heat dissipation by enlarging the surface area exposed to the
- D. They direct the flow of air to the hottest areas of the radiator.
6. The radiator of an air-conditioned vehicle has how many fins per inch?
- A. Five
- B. Six
- C. Seven
- D. Eight
7. The lower radiator hose connects the radiator to the _.
- A. thermostat housing
- B. engine block water passages
- C. cylinder head water passages
- D. water pump inlet
8. What is the purpose of the hose spring used in the lower radiator hose?
- A. To prevent the hose from collapsing
- B. To protect the system against damage
- C. To allow the hose to be shaped to clear moving parts
- D. To allow the hose to withstand engine vibration
9. Which is NOT a function of the radiator pressure cap?
- A. Seals the top of the radiator filler neck to prevent leakage.
- B. Pressurizes the system to raise the boiling point of the coolant.
- C. In an open system, allows coolant to flow into and from the coolant
- D. Relieves excess pressure to protect the system against damage.
10. A radiator is equipped with a 12-pound pressure cap. What effect does this
cap have on the boiling point of the coolant?
- A. Raises it by 36°
- B. Lowers it by 26°
- C. Raises it by 16°
- D. Lowers it by 6°
11. What part of the water pump provides a mounting place for the fan and belt?
- A. Hub
- B. Housing
- C. Shaft
- D. Impeller
12. A bent fan blade will NOT cause which condition?
- A. Worn fan belt
- B. Vibration
- C. Excessive wear of the water pump shaft
- D. Noise
13. When an electric fan is used, the fan switch closes to operate the fan when
coolant temperature reaches approximately what temperature?
- A. 170°F
- B. 190’F
- C. 210°F
- D. 230°F
14. A coolant distribution tube is used in cooling systems of an L-head engine
in order to _____ .
- A. disperse hot coolant that enters the top tank of the radiator
- B. distribute the coolant equally between the cylinder block and the cylinder
- C. direct the coolant to the cylinder head only
- D. direct the coolant to the hottest parts of the cylinders
15. A ferrule type coolant director is used in the cooling system of I-head
engines to direct a jet of coolant towards the exhaust .
- A. valve guides
- B. valve seats
- C. ports
- D. manifold heat valve
16. What type of thermostat is used in a modem pressurized cooling system?
- A. Pellet
- B. Bypass
- C. Bellows
- D. Butterfly
17. A thermostat rated at 190°F will fully open at what temperature?
- A. 190°F
- B. 200°F
- C. 210°F
- D. 220°F
18. Why do some stationary engines and large trucks have shutters placed in
front of the radiators?
- A. To restrict the flow of air through the radiator
- B. To prevent foreign matter from damaging the radiator core
- C. To eliminate the need for a cooling fan
- D. To provide slower warm-up and operating temperatures
19. Radiator shutters used on large trucks are opened by what type of pressure?
- A. Water
- B. Spring
- C. Hydraulic
- D. Air
20. A temperature warning light warns of an overheating condition about coolant
- A. 5° to 10° below
- B. 5° to 10° above
- C. 10° to 15° below
- D. 10° to 15° above
21. A coolant mixture containing 60% antifreeze provides adequate protection
against freezing to what maximum temperature?
- A. -20°F
- B. -34°F
- C. -50°F
- D. -62°F
22. What is the most common method of flushing?
- A. Reverse
- B. Fast
- C. Chemical
- D. Fast-reverse
23. When a pressure tester is being used to test a radiator cap, what is the
minimum length of time, in minutes, that the pressure should be held to indicate
that the cap is operational?
- A. 4
- B. 3
- C. 2
- D. 1
24. When a combustion leak is detected in the cooling system, the fluid in the
block test will change color from blue to _____.
- A. green
- B. orange
- C. yellow
- D. purple
25. Correct fan belt tension can be determined by measuring the .
- A. distance between the belt pulleys
- B. width of the belt
- C. deflection of the belt between pulleys
- D. distance between pulleys and then subtracting the width of the belt
26. Which is NOT a function of the engine lubrication system?
- A. Reduces friction between moving parts.
- B. Transfers heat.
- C. Cleans the inside of the engine by removing contaminants.
- D. Assures maximum wear on moving parts.
27. Oil service ratings are determined by what agency?
- A. Society of Automotive Engineers
- B. Society of Petroleum Engineers
- C. American Petroleum Institute
- D. American Automotive Institute
28. Which is an operating principle of the rotary oil pump?
- A. The inner rotor is centrally located in the outer rotor.
- B. The inner rotor causes the outer rotor to spin.
- C. The outer rotor causes the inner rotor to spin.
- D. A small pocket is formed on the inlet side of the pump.
29. Which action is an operating principle of a gear type oil pump?
- A. Both gears are independently driven by shafts.
- B. Both gears turn in the same direction.
- C. Pum> action forces oil to pass between the gear teeth.
- D. The pump is driven by the crankshaft or distributor.
30. In an engine lubrication system, where is the oil strainer located?
- A. In the oil return line to the crankcase
- B. At the inlet of the oil pump pickup tube
- C. In the discharge line from the oil pump
- D. At the inlet side of the oil galleries
31. Why are dirt, water, and sludge unable to pass through an oil strainer with
- A. All oil is collected from the surface of the oil in the oil pan.
- B. The mesh of the screen allows only the lubricating oil to pass.
- C. The strainers are located above the bottom of the oil pan.
- D. The strainers are designed to allow oil pumps to pick up oil based on their
32. Which factor is an advantage of using a full flow oil filter in a
- A. All oil is circulated through the filter before it reaches the engine.
- B. The filter does not need to be changed as often as other filters.
- C. The filter never permits any unfiltered oil to reach the moving parts of the
- D. The filter diverts a small amount of oil and returns it to the oil pan.
33. The sending unit for an oil pressure warning light is calibrated to come on
when oil pressure drops below what psi level?
- A. 10
- B. 15
- C. 20
- D. 25
34. In a mechanical type oil pressure gauge, the oil line is tapped at what
- A. Base of the oil filter
- B. Oil gallery leading from the oil pump
- C. Oil gallery leading from the side of the engine
- D. Oil filter housing unit
35. An operator reports that a vehicle is using a lot of oil; however, there is
no sign of external leakage. What color smoke is a sign of internal oil leakage?
- A. Gray
- B. Black
- C. White
- D. Blue
36. Which condition is NOT a cause of low oil pressure?
- A. Worn main bearings
- B. Worn oil pump
- C. Restricted oil gallery
- D. Weak or broken pressure relief valve spring
37. Which condition is indicated by a high oil pressure reading?
- A. Worn engine bearings
- B. Overheated engine
- C. Blocked oil passage
- D. Cracked oil pickup tube
38. In changing engine oil, when should you drain the oil from the vehicle?
- A. When the engine is warm
- B. While the engine is cold
- C. Anytime
- D. Whenever the vehicle is deadlined
- 39. When replacing a spin-on filter, you should turn the filter how far after
contact is made with the base?
- A. One-fourth turn
- B. One-third turn
- C. One-half turn
- D. Full turn