Quiz 2 - Lubricating And Cooling Systems

The engine's lubrication system performs multiple functions. It holds an adequate supply of oil to ensure proper lubrication of the engine's moving parts. 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 components receive proper lubrication. Therefore, all of the options mentioned in the question are correct functions of the engine's lubrication system.

The correct answer is to pump up the pressure 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. Pumping the pressure up to this rating ensures that the system is tested under the conditions it is designed to withstand, without exceeding its limits. Pumping the pressure higher than the pressure cap rating could potentially cause damage to the cooling system.

Underheating of an engine can lead to several harmful effects. Firstly, it can cause high tailpipe emissions as the engine operates inefficiently, resulting in incomplete combustion of fuel and increased production of pollutants. Secondly, underheating can lead to sludge buildup in the oil, as the engine does not reach its optimal operating temperature to burn off impurities. This can reduce the engine's performance and potentially lead to damage. Lastly, underheating can result in poor gas mileage as the engine struggles to reach its optimal efficiency, requiring more fuel to produce the same amount of power.

The recommended mixture of water and antifreeze to form engine coolant is 50/50. This means that the coolant should be a 50% mixture of water and a 50% mixture of antifreeze. This mixture provides the optimal balance of cooling and freeze protection for the engine. Too much water can lead to overheating, while too much antifreeze can reduce the coolant's ability to dissipate heat. Therefore, a 50/50 mixture is the most commonly recommended ratio for engine coolant.

When an engine overheats, the intense heat can cause damage to the combustion chamber parts. The excessive heat can cause warping or cracking of the cylinder head, pistons, and valves. This can lead to a loss of compression, misfires, and ultimately engine failure. Therefore, damage to combustion chamber parts is a likely harmful effect of engine overheating.

Both Technician A and Technician B are correct. Engine oil is indeed used to clean, cool, and lubricate the engine. It helps to remove dirt and debris from the engine components, absorbs heat generated by the engine, and reduces friction between moving parts. Additionally, engine oil also helps to seal some internal engine parts, such as the piston rings, preventing oil leakage and maintaining proper compression.

Both technicians A and B are correct. Technician A is correct in stating that low engine oil pressure can be caused by worn engine bearings. Worn engine bearings can lead to excessive clearance, which can result in a decrease in oil pressure. Technician B is also correct in mentioning that oil viscosity, temperature, and contamination can affect oil pressure. The viscosity of the oil can impact its ability to flow and maintain pressure, while temperature changes can also affect the oil's viscosity. Additionally, contamination, such as dirt or debris, can restrict the flow of oil and result in lower pressure.

The water pump in most automotive applications is driven by the crankshaft. The crankshaft is a vital component of the engine that converts the reciprocating motion of the pistons into rotational motion. It is directly connected to the water pump through a pulley and belt system. As the crankshaft rotates, it transfers its power to the water pump, which circulates coolant throughout the engine to prevent overheating.

Both Technician A and Technician B are correct. Technician A is correct in stating that a leaking head gasket could explain the presence of coolant in the engine's crankcase. A leaking head gasket can cause coolant to mix with the oil, leading to coolant contamination in the crankcase. Technician B is correct in stating that coolant that is a milky brown color indicates contamination with either engine or automatic transmission oil. The milky brown color is a result of the coolant and oil mixing together. Therefore, both technicians are correct in their statements.

Modern cooling systems are pressurized to raise the coolant's boiling point. By increasing the pressure, the boiling point of the coolant also increases, allowing it to absorb more heat from the engine without evaporating. This helps prevent the coolant from boiling and potentially causing engine damage or overheating.

Both Technician A and Technician B are correct. The 'S' service rating system does indeed rate oil for gasoline engines and refers to the level of additives and other characteristics of the oil's makeup. Additionally, an SL rated oil can be used in place of an SH rated oil, as SL is a more recent and improved rating.

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 ensure optimal performance and longevity of the engine.

Both Technician A and Technician B are correct. An electric cooling fan may come on without the ignition being turned on because it can be controlled by the engine control computer. The engine control computer monitors the engine temperature and activates the cooling fan as needed to prevent overheating, even if the ignition is not turned on. Therefore, both technicians are correct in their statements.

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. If the PCV system is faulty, it may not be able to properly regulate the pressure and flow of these gases, 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 and consumed. Therefore, both A (faulty PCV system) and B (worn piston rings) can be likely causes of excessive oil consumption.

A non-operational electric cooling fan in a vehicle is responsible for cooling the engine and preventing it from overheating. At high speeds, the airflow created by the movement of the vehicle can provide some cooling effect, compensating for the non-functional fan. However, at low speeds, there is less airflow, and the engine relies heavily on the cooling fan. Therefore, if the electric cooling fan is not working, the most likely symptom would be overheating at low speeds when there is insufficient airflow to cool the engine effectively.

Excessive engine valve lifter wear would not cause low oil pressure because the valve lifters are not directly related to oil pressure. The valve lifters are responsible for opening and closing the engine valves, while oil pressure is primarily affected by factors such as the oil pump, oil viscosity, and any blockages in the oil passages. Therefore, excessive engine valve lifter wear would not directly impact oil pressure.

Technician B is correct. When an engine experiences decreased oil pressure, valvetrain noise is a common symptom. This is because the valves and lifters rely on proper lubrication from the oil to function smoothly. Decreased oil pressure can cause the valves and lifters to become noisy and potentially lead to further engine damage if not addressed. Piston slap, on the other hand, is a separate issue that is not directly related to decreased oil pressure.

Neither Technician A nor Technician B is correct. Engine oil viscosity ratings are determined by the Society of Automotive Engineers (SAE) and are represented by a numerical code. The first number in the code indicates the oil's viscosity at low temperatures, and the second number represents its viscosity at high temperatures. Therefore, a low-weight oil may not necessarily work best in high-temperature regions, as other factors such as the engine's design and operating conditions also play a role. Additionally, not all multi-viscosity oils are interchangeable, as different engines may require specific viscosity grades for optimal performance and protection.

Technician A is not correct because extended life coolant may not necessarily be more environmentally friendly. Technician B is also not correct because two year coolant (green) cannot be used to top off all automotive cooling systems, as different vehicles may require different types of coolant. Therefore, neither Technician A nor Technician B is correct.

Neither Technician A nor Technician B is correct. High oil pressure does not cause valve cover gasket leaks. Valve cover gasket leaks are typically caused by worn or damaged gaskets. Similarly, low oil pressure is not caused by a faulty PCV (Positive Crankcase Ventilation) system. Low oil pressure can be caused by a variety of issues such as a malfunctioning oil pump or a leak in the oil system.