1.
Which of the following is a function of the engine's lubrication system?
Correct Answer
D. All of the above
Explanation
The engine's lubrication system performs multiple functions. It holds an adequate supply of oil to ensure that there is enough lubrication for the engine's components. It also removes contaminants from the oil, preventing them from causing damage to the engine. Additionally, the lubrication system delivers oil to all necessary areas of the engine, ensuring that all moving parts are properly lubricated. Therefore, the correct answer is "All of the above."
2.
Technician says that the 'S' service rating system (SA, SB, SC,etc.) rates oil for gasoline engines and refers to the level of additives and other characteristics of the oil's makeup. Technician B says that an SL rated oil can be used in place of an SH rated oil. Who is correct?
Correct Answer
C. Both A and B
Explanation
Both technicians A and B are correct. Technician A is correct in stating that the 'S' service rating system rates oil for gasoline engines and refers to the level of additives and other characteristics of the oil's makeup. Technician B is also correct in stating that an SL rated oil can be used in place of an SH rated oil. The SL rating is a newer and more advanced specification than the SH rating, so it is backward compatible and can be used in place of the older SH rated oil.
3.
Engine oil viscosity ratings are being discussed. Technician A says a low-weight oil works best in high-temperature regions. Technician B says that all multi-viscosity oils are interchangeable. Who is correct?
Correct Answer
D. Neither A nor B
Explanation
Neither Technician A nor Technician B is correct. Engine oil viscosity ratings determine the oil's ability to flow at different temperatures. Technician A is incorrect because a low-weight oil, such as 5W-20, works best in cold temperatures, not high-temperature regions. Technician B is incorrect because not all multi-viscosity oils are interchangeable. The correct viscosity rating for an engine depends on the manufacturer's specifications and the climate in which the vehicle operates.
4.
Technician A says engine oil is used to cool, clean, and lubricate the engine. Technician B says engine oil helps seal some internal engine parts. Who is correct?
Correct Answer
C. Both A and B
Explanation
Both Technician A and Technician B are correct. Engine oil is indeed used to cool, clean, and lubricate the engine. It helps in reducing friction between moving parts, which in turn helps to cool the engine. Additionally, engine oil also helps in cleaning the engine by carrying away dirt and debris. Furthermore, it helps in sealing some internal engine parts to prevent leaks and maintain proper pressure. Therefore, both technicians are correct in their statements.
5.
Engine oil pressure is being discussed. Technician A says low pressure may be caused by worn engine bearings. Technician B says oil viscosity, temperature, and contamination can affect oil pressure. Who is correct?
Correct Answer
C. Both A and B
Explanation
Both Technician A and Technician B are correct. Low oil pressure can be caused by worn engine bearings, as they can lead to a loss of oil pressure. Additionally, oil viscosity, temperature, and contamination can also affect oil pressure. If the oil is too thin (low viscosity), it may not provide enough pressure. Similarly, if the oil is too thick (high viscosity) or contaminated, it can impede the flow and result in low oil pressure. Therefore, both technicians are correct in their explanations.
6.
When an engine experiences decreased oil pressure, Technician A says tha piston slap is a likely initial symptom. Technician B says that valvetrain noise is common with decreased oil pressure. Who is correct?
Correct Answer
B. B only
Explanation
Technician B is correct. Decreased oil pressure is commonly associated with valvetrain noise. This is because the valvetrain relies on proper lubrication provided by the oil to operate smoothly. When oil pressure decreases, the valvetrain components may not receive enough lubrication, leading to increased friction and noise. On the other hand, piston slap is not typically related to decreased oil pressure. Piston slap is a knocking sound that occurs when the piston moves within the cylinder bore, usually due to excessive clearance. This issue is not directly related to oil pressure.
7.
Which of the following would not cause low oil pressure?
Correct Answer
C. Excessive engine valve lifter wear
Explanation
Excessive engine valve lifter wear would not cause low oil pressure because the valve lifters are not directly responsible for maintaining oil pressure. Oil pressure is primarily regulated by the oil pump, which circulates oil throughout the engine. Excessive engine valve lifter wear may cause other issues such as noisy operation or poor performance, but it would not directly result in low oil pressure.
8.
Which of the following would be a likely cause excessive oil consumption?
Correct Answer
D. Both A and B
Explanation
Both a faulty PCV system and worn piston rings can contribute to excessive oil consumption. The PCV (Positive Crankcase Ventilation) system is responsible for removing blow-by gases from the engine's crankcase and returning them to the intake manifold to be burned off. If the PCV system is faulty, it may not be able to properly regulate the pressure in the crankcase, leading to increased oil consumption. Worn piston rings, on the other hand, can allow oil to leak into the combustion chamber, where it is burned off and consumed. Therefore, both A (faulty PCV system) and B (worn piston rings) can be likely causes of excessive oil consumption.
9.
Technician A says high oil pressure will cause valve cover gasket leaks. Technician B says low oil pressure can be caused by a faulty PCV system. Who is correct?
Correct Answer
D. Neither A nor B
Explanation
Neither Technician A nor Technician B is correct. High oil pressure does not cause valve cover gasket leaks. Valve cover gasket leaks are usually caused by worn-out or damaged gaskets. On the other hand, low oil pressure is not caused by a faulty PCV (Positive Crankcase Ventilation) system. Low oil pressure can be caused by various factors such as a faulty oil pump, worn-out bearings, or low oil level.
10.
Technician A says that extended life coolant is more environmently friendly. Technician B says two year coolant (green) can be used to top off all automotive cooling systems. Who is correct?
Correct Answer
D. Neither A nor B
Explanation
Neither Technician A nor Technician B is correct. Extended life coolant is not necessarily more environmentally friendly, as it depends on the specific formulation and disposal methods. Additionally, two-year coolant (green) cannot be used to top off all automotive cooling systems, as different vehicles may require different types of coolant.
11.
In most automotive applications, the water pump is driven by the:
Correct Answer
C. Crankshaft
Explanation
The water pump in most automotive applications is driven by the crankshaft. The crankshaft is responsible for converting the reciprocating motion of the pistons into rotational motion, and it is connected to various components of the engine, including the water pump. The rotation of the crankshaft transfers power to the water pump, which allows it to circulate coolant throughout the engine, maintaining proper temperature and preventing overheating.
12.
Why are modern cooling systems pressurized?
Correct Answer
A. To raise the coolant's boiling point
Explanation
Modern cooling systems are pressurized in order to raise the coolant's boiling point. When the coolant is pressurized, it can reach higher temperatures without boiling. This is important because higher temperatures can be reached in the engine, and without pressurization, the coolant would boil and evaporate, leading to a loss of coolant and potential damage to the engine. By raising the boiling point, the pressurized cooling system can effectively regulate the engine temperature and prevent overheating.
13.
What is the most likely symptom of a vehicle with a non-operational electric cooling fan?
Correct Answer
B. Overheating at low speeds
Explanation
A non-operational electric cooling fan in a vehicle would result in a lack of airflow to cool the engine. At low speeds, there is less natural airflow, so the engine relies more on the electric cooling fan to prevent overheating. Therefore, the most likely symptom of a vehicle with a non-operational electric cooling fan would be overheating at low speeds.
14.
The typical recommended mixture of water and antifreeze to form engine coolant is:
Correct Answer
B. 50/50
Explanation
The recommended mixture of water and antifreeze to form engine coolant is 50/50. This means that the coolant should be composed of equal parts of water and antifreeze. This mixture provides the optimal balance of cooling and anti-freezing properties for the engine. Too much water can cause the coolant to freeze in cold temperatures, while too much antifreeze can reduce the coolant's ability to dissipate heat effectively. A 50/50 mixture ensures that the coolant can effectively regulate the engine's temperature in both hot and cold conditions.
15.
Most manufacturers recommend that cooling systems with conventional (green) antifreeze should be drained, flushed, and filled every:
Correct Answer
C. Two years
Explanation
Manufacturers recommend that cooling systems with conventional (green) antifreeze should be drained, flushed, and filled every two years. This is because over time, antifreeze can break down and become less effective at preventing corrosion and maintaining proper engine temperature. Regular maintenance of the cooling system helps to ensure optimal performance and prevent potential damage to the engine.
16.
When pressure testing a cooling system, the pressure applied should be
Correct Answer
B. Pumped up to the pressure cap rating
Explanation
When pressure testing a cooling system, the pressure should be pumped up to the pressure cap rating. This is because the pressure cap rating indicates the maximum pressure that the cooling system can handle without causing any damage or leaks. Pumping the pressure up to this rating ensures that the system is tested under the maximum pressure it will experience during normal operation, allowing any potential issues to be identified and addressed before they cause problems.
17.
Technician A says a leaking head gasket could explain the presence of coolant in the engine's crankcase. Technician B says that coolant that is a milky brown color has been contaminated with either engine or automatic transmission oil. Who is correct?
Correct Answer
C. Both A and B
Explanation
Both Technician A and Technician B are correct. Technician A is correct because a leaking head gasket can allow coolant to mix with the engine oil, resulting in the presence of coolant in the engine's crankcase. Technician B is correct because coolant that appears milky brown in color is a sign that it has been contaminated with either engine or automatic transmission oil. Therefore, both technicians are providing accurate explanations for the given situation.
18.
Technician A says an electric cooling fan may come on without the ignition being turned on. Technician B says an electric cooling fan may be controlled by the engine control computer. Who is correct?
Correct Answer
C. Both A and B
Explanation
Both Technician A and Technician B are correct. An electric cooling fan may come on without the ignition being turned on, as it can be controlled by the engine control computer. The engine control computer monitors the engine's temperature and can activate the cooling fan as needed, even when the ignition is off. Therefore, both technicians are correct in their statements.
19.
What is a likely harmful effect of an engine overheating?
Correct Answer
A. Damage to the combustion chamber parts
Explanation
When an engine overheats, the excessive heat can cause damage to the combustion chamber parts. The combustion chamber is where the fuel and air mixture is ignited to produce power, and if it becomes damaged, it can lead to reduced engine performance, misfires, and even engine failure. Overheating can cause the metal components in the combustion chamber to warp, crack, or become distorted, which can disrupt the combustion process and result in costly repairs or replacement of parts.
20.
What is the likely harmful effect of engine underheating?
Correct Answer
D. All of the above
Explanation
Engine underheating can have several harmful effects. Firstly, it can lead to high tailpipe emissions as the engine does not reach its optimal operating temperature, causing incomplete combustion of fuel and increased pollution. Secondly, underheating can result in sludge buildup in the oil, as the engine does not get hot enough to evaporate moisture and contaminants, leading to reduced lubrication and potential damage to engine components. Lastly, engine underheating can also cause poor gas mileage, as the engine operates less efficiently when it is not at the correct temperature. Therefore, all of the given options are likely harmful effects of engine underheating.