Download Lubrication systems test QUESTIONS | EXAM NEW VERSION LATEST UPDATE 2025-2026 and more Exams Aviation in PDF only on Docsity!
Lubrication systems test QUESTIONS |
EXAM NEW VERSION LATEST UPDATE
2025 - 2026 WITH ACCURATE ANSWERS
GUARANTEED PASS BEST STUDYING
MATERIAL
1. Tech A says the primary job of anti-wear additives is to protect the camshaft and lifters. Tech B says ZDDP has been commonly used as an anti-wear additive. Who's right? A. Tech A B. Tech B C. Both D. Neither Correct Answer: C. Both Rationale: Anti-wear additives like ZDDP (zinc dialkyldithiophosphate) are primarily used to protect components like camshafts and lifters from metal-to-metal wear. 2. Tech A says most manufacturers recommend a minimum of 25 psi of oil pressure for every 1000 rpm. Tech B says short trips allow sludge to accumulate. Who's right? A. Tech A B. Tech B C. Both D. Neither Correct Answer: B. Tech B Rationale: Short trips prevent oil from reaching operating temperature, leading to sludge buildup. The 25 psi per 1000 rpm rule is a general guideline but not universal.
3. Synthetic oil molecules are all the same size. A. True B. False Correct Answer: A. True Rationale: Synthetic oils are engineered at the molecular level to be uniform in size and shape, enhancing performance. 4. Tech A says leaking vacuum lines can allow dirt to be drawn into an engine. Tech B says a horizontally mounted oil filter has an anti-drain back valve. Who's right? A. Tech A B. Tech B C. Both D. Neither Correct Answer: C. Both Rationale: Both statements are correct. Vacuum leaks can introduce contaminants, and horizontal filters often include anti-drain back valves to maintain oil supply. 5. Since the early 1960s, road draft tubes have been used to replace PCV systems. A. True B. False Correct Answer: B. False Rationale: PCV (Positive Crankcase Ventilation) systems replaced road draft tubes starting in the early 1960s for better emissions control. 6. Tech A says additive packages make up as much as one-third of the volume of a container of oil. Tech B says friction modifiers help oil stick to metal surfaces. Who's right? A. Tech A B. Tech B C. Both D. Neither Correct Answer: A. Tech A
10. The function of engine oil includes: A. Reduce friction B. Cool the engine C. Clean the engine D. All of the above Correct Answer: D. All of the above Rationale: Oil lubricates, cools, cleans, seals, and prevents corrosion. 11. What effect does temperature have on lubricating oil? A. No effect B. Changes its pH C. Affects viscosity D. Increases detergent action Correct Answer: C. Affects viscosity Rationale: Oil becomes thinner when hot and thicker when cold. 12. In "Aeroshell 100 Oil SAE 50W," the "W" means: A. Weight B. Winter C. With additives D. Wet sump Correct Answer: B. Winter Rationale: The "W" indicates the oil is rated for winter use and cold-start performance. 13. In "Aeroshell 100W Oil SAE 50," the "W" indicates: A. Winter use B. Water-based oil C. Ashless dispersant D. Weight rating Correct Answer: C. Ashless dispersant Rationale: In this designation, "W" refers to oil with ashless dispersant additives.
14. Each oil tank must have an expansion space of: A. 5% of capacity B. 10% of capacity C. 25% of capacity D. None Correct Answer: B. 10% of capacity Rationale: This prevents overfilling and allows for oil expansion. 15. Why does a gear-type oil pump require a relief valve? A. To increase pressure B. To cool the oil C. To prevent overpressure D. To reduce flow Correct Answer: C. To prevent overpressure Rationale: Gear pumps are positive displacement types and need a relief valve to avoid system damage. 16. Magnetic chip detectors are used to detect: A. Carbon buildup B. Water in oil C. Ferrous particles D. Non-metallic debris Correct Answer: C. Ferrous particles Rationale: Magnetic detectors attract and hold metallic debris for early failure detection. 17. Federal Aviation Regulations require the oil cap to be marked with: A. Grade B. Engine type C. "OIL" D. Manufacturer
C. Viscosity D. Pressure Correct Answer: C. Viscosity Rationale: Viscosity defines an oil’s thickness and flow behavior.
22. Viscosity is measured using a Saybolt Universal Thermometer. A. True B. False Correct Answer: B. False Rationale: The correct device is the Saybolt Universal Viscosimeter. 23. Which oil filter uses cleaner blades that comb debris from discs? A. Cuno filter B. Cartridge filter C. Spin-on filter D. Full-flow filter Correct Answer: A. Cuno filter Rationale: Cuno filters use rotating blades to remove contaminants from stacked discs. 24. Oil temperature is typically measured: A. After the filter B. Inside the cooler C. Before entering hot sections D. In the tank Correct Answer: C. Before entering hot sections Rationale: This provides an accurate reading of the oil feeding into the engine. 25. The high operating temperatures of turbine engines led to the development of: A. Detergent oils B. Semi-synthetic oils
C. Synthetic oils D. Petroleum oils Correct Answer: C. Synthetic oils Rationale: Synthetic oils can withstand the extreme heat of turbine engines.
26. If metal is found on a chip detector, you should: A. Replace the detector B. Ignore it C. Investigate the source D. Add more oil Correct Answer: C. Investigate the source Rationale: Metal presence may indicate internal damage or wear. 27. In a dry sump system, the oil pump is located at the: A. Oil tank B. Oil inlet C. Crankshaft D. Rocker arms Correct Answer: B. Oil inlet Rationale: The pump feeds oil from the tank into the engine. 28. The dry sump scavenge pump sends oil to the: A. Oil filter B. Bearings C. Oil tank D. Crankcase Correct Answer: C. Oil tank Rationale: The scavenge pump collects used oil and returns it to the reservoir.
Correct Answer: C. On the oil cooler Rationale: The valve regulates oil flow through the cooler.
33. Which component limits oil pressure to a maximum value? A. Scavenge pump B. Oil tank C. Oil pressure regulating valve D. Heat exchanger Correct Answer: C. Oil pressure regulating valve Rationale: It prevents overpressurization of the system. 34. Oil pressure is measured: A. Before the pump B. After the pump C. In the oil pan D. At the filter Correct Answer: B. After the pump Rationale: Pressure is taken downstream of the pump to reflect engine oil supply. 35. The surge protection valve in the oil cooler prevents: A. Oil leaks B. Cold oil flow C. Bursting of the cooler D. Viscosity change Correct Answer: C. Bursting of the cooler Rationale: The valve relieves excess pressure to protect components. 36. In a turbine engine, the fuel/oil heat exchanger: A. Cools fuel B. Heats oil
C. Heats fuel and cools oil D. Separates fuel from oil Correct Answer: C. Heats fuel and cools oil Rationale: It transfers heat from hot oil to fuel to improve both systems.
37. Friction is defined as: A. Oil resistance B. Surface tension C. Rubbing of one object against another D. Air drag Correct Answer: C. Rubbing of one object against another Rationale: Friction is the resistance to motion between two contacting surfaces. 38. The lowest temperature at which oil flows is called: A. Viscosity B. Freeze point C. Flash point D. Pour point Correct Answer: D. Pour point Rationale: Pour point is the minimum temperature where oil remains fluid. 39. Two types of oil coolers commonly used are: A. Air-oil and fuel-oil B. Air-fuel and liquid-oil C. Fan and coil D. Refrigerated and hydraulic Correct Answer: A. Air-oil and fuel-oil Rationale: These types are most effective in engine cooling systems.
44. Two important characteristics of engine oil are: A. It must be synthetic and thick B. It must be light enough to flow and heavy enough to protect C. It must be detergent and clear D. It must evaporate easily Correct Answer: B. It must be light enough to flow and heavy enough to protect Rationale: Proper oil viscosity ensures circulation and adequate film strength. Oil is being discussed. Tech A says oil never wears out. Tech B says there are many additives in oil that will become depleted during engine operation. Who is correct? - Ans - Both Tech A says that pleated paper is generally used in bypass oil filters. Tech B says a relief valve that is stuck closed will result in high oil pressure at idle. Who is right? - Ans - Both Tech A says too much oil can cause excessive oil consumption. Tech B says to much oil in the crankcase can cause aeration of the oil. Who's right? - Ans - Both What does SAE stand for? - Ans - Society of Automotive Engineers What could happen to an oil that is too low in viscosity at normal engine operating temperatures? - ANSWER it may become so thin that the oil film between moving parts is easily broken, resulting in premature wear. What are some of the factors that must be considered by an engine manufacturer in determining the proper grade of oil for a particular engine? - ANSWER The operating load and temperature as well as the rotational speed.
Why do aircraft reciprocating engines use a relatively high viscosity oil? - ANSWER Because they usually have large operating clearances, and operate at high temperatures and pressures. Name some oil contaminants. - ANSWER Metal particles, dirt, carbon, moisture and acids. What is a possible indication of low oil pressure together with high oil temperature? - ANSWER A low or inadequate oil supply. In ashless dispersant (AD) oils, what function does the dispersant perform? - ANSWER The dispersant causes sludge-forming materials to repel each other and remain in suspension until they can be trapped by the oil filter or drained. This keeps the oil passages and ring grooves free of harmful deposits, and the inside of the engine clean. Why do oil reservoirs have expansion space/ - ANSWER To provide for oil foaming, thermal expansion, and air in the return oil. What could cause oil foaming? - ANSWER Diluted oil, contaminated oil, and the oil level being too high. What controls oil pressure in a gear-type oil pressure pump? - ANSWER An oil pressure relief valve. What function does an oil cooler bypass valve perform? - ANSWER It directs the oil either through the cooler or around it in order to maintain proper operating oil temperatures. What could be a possible indication if the oil cooler passage becomes obstructed? - ANSWER A high oil temperature. Where is the oil temperature bulb usually located? - ANSWER At the engine oil inlet.
Give an example of each type of bearing - Ans - A. Friction example - a crankshaft B. Anti Friction example - a wheel bearing What do we use to control friction - Ans - Lubrication or oil Name three functions of oil - Ans - A. clean B. cool C. seal List three oil additives - Ans - A. Detergent B. Oxidation inhibitor C. Friction Modifiers Define viscosity - Ans - Oil's resistance to pouring Describe what multi-grade oil is - Ans - An oil with more than one viscosity What is the base for synthetic oil - Ans - crude oil How often should you change your oil & filter - Ans - every 3,000 miles Name two types of oil filters - Ans - A. Sealed cartridge B. Removable Element How tight should you tighten an oil filter - Ans - Hand tight Before installing a new oil filter, you should check the old filter for what? - Ans - The seal After every oil change you should always check for what? - Ans - Leaks
The first crankcase vent system was called what? - Ans - Road Draft Tube What does PCV stand for? - Ans - Positive Crankcase Ventilation What will happen if pressure builds up in the crankcase? - Ans - Oil leaks at the gasket Name two types of oil pressure gauges - Ans - A. Mechanical B. Electrical Which type of OP gauge is more accurate - Ans - Mechanical What does API stand for? - Ans - American Petroleum Institute What does SF stand for? - Ans - S = Service or Gas Engines F = year 1980 What does CC stand for? - Ans - C = Commercial or Diesel Engines C = year 1980 What does SAE stand for? - Ans - Society of Automotive Engineers What does 10W - 30 stand for? - Ans - Multi Viscosity or Multi grade oil The two types of constant displacement pumps in reciprocating engine lubrication systems are the _____ and ___________ pumps. - Ans - gear, gerotor Depth filter - Ans - Consists of a matrix of fibers which are closely packed to a depth of about one inch.
The purpose of a pressure relief valve in the oil system, is to keep the excessive pressure generated by the oil pump at high RPM from damaging the engine. T or F - Ans - True Most pressure relief valves are spring loaded in the open position. T or F - Ans - False The greater an oil pressure relief valves spring pressure, the higher the oil pressure will be. T or F - Ans - True Where is the oil filter located within the lubrication system? - Ans - After the oil pump Which oil filtration system filters 100 percent of the engine oil? - Ans - both full-flow and bypass systems The filter in a full-flow oil filtration system is installed in series with the oil pump. T or F - Ans - True When installed in a dry-sump system, the oil cooler is typically located in the oil supply line between the oil reservoir and the oil pump. T or F - Ans - False The valve which controls the amount of oil that flows through the core of an oil cooler is known as what? - Ans - Thermostatic control valve, bypass valve, flow control valve When replacing a disposable filter, what is common practice? - Ans - Cut it open to inspect for metal particles To increase oil pressure you should turn the adjustment screw clockwise. T or F - Ans - True What are the functions of lubricating oil? - Ans - Absorbs heat, seals, cushions, cleans, protects against corrosion, reduces friction
Viscosity - Ans - a measure of oils resistance to flow Viscosity index - Ans - Standard used to identify the rate of change in viscosity for a given change in temperature Specific Gravity - Ans - Comparison of an oil's weight to the weight of an equal volume of distilled water at a specified temperature. Cloud Point - Ans - Temperature at which paraffin wax and other solids normally held in a solution of oil begin to solidify and separate into tiny crystals. Pour Point - Ans - The lowest temperature at which oil can flow. Flash Point - Ans - Temperature at which oil begins to emit ignitable vapors. Fire Point - Ans - Temperature at which oil emits sufficient vapor to support a flame. Straight Mineral Oil - Ans - Limited to new of newly overhauled engines during break-in. Ashless-Dispersant Oil - Ans - Most commonly used oil in reciprocating engines. Multi-Viscosity Oil - Ans - Provides adequate lubrication over a wider temperature range. Synthetic Oils - Ans - Made by synthesizing raw materials into a base stock rather than refinish base stock from crude oil. Pressure Lubrication - Ans - Primary method of lubrication.
