NOCTI Diesel Technology Practice Test

These questions are part of the practice quiz. Start practicing

• Which statement is true about lights wired in parallel?
• The symbol for ohm represents which electrical property?
• Diesel engine speed is controlled by the
• A compression test shows that one cylinder is low. When performing a cylinder leakage test, air is heard coming out of the dipstick tube. This would indicate
• Which device is typically used to control high-current circuits with a low-current signal?
• Vehicle alignment will not correct
• A _______ fire extinguisher should be used on a diesel electrical fire.
• What type of flared fitting is used in hydraulic systems?
• A battery often requires adding extra water because of overcharging.
• Overcharging a battery commonly causes the water to evaporate.
• Which component in an alternator is responsible for producing the magnetic field that induces current?
• Teflon tape should be applied to pneumatic line fittings using which steps?
• Vehicle breakdowns often occur due to lines that are
• What type of coolant pump does a typical water-cooled engine have?
• Oily rag storage should be in a
• To adjust steering knuckle vertical play, the technician would
• When using a pedestal grinding wheel, a technician must wear
• A built-in hydrometer indicator showing green on a battery usually indicates the battery is fully charged.
• To check the flywheel face runout, secure the dial indicator base to which surface?
• When adjusted properly, the free travel of a manually adjusted S-cam slack adjusted should be
• Which device regulates the idling speed and maximum speed of the engine by controlling the rate of fuel delivery?
• When diagnosing an alternator, which components should be checked for electrical continuity?
• An average circuit voltage on a 12-volt system is
• When installing a housing with multiple bolt holes, which practice is correct?
• In oil cooler, the heat transfer occurs to which medium?
• Which component is responsible for cooling the compressed air before it enters the combustion chamber?
• Which component connects the steering box output to the drag link?
• Which setup ensures an accurate flywheel runout measurement when using a dial indicator?
• U-bolts should be replaced every time that the springs are replaced.
• The technician should electrically check the _______ within the alternator
• Glow-plugs are used to help with cold starts by which action?
• Using parabolic leaf springs provides smoother riding comfort and less stiffness than
• According to environmental regulations, when a hazardous material is spilled on a shop floor, what should the technician do?
• If the engine warms up slowly and stays cold, the most likely cause is a faulty thermostat.
• A customer drives a vehicle into a shop and wants to know why the upper radiator hose collapses as the engine cools off. The most likely cause is a defective
• Which term describes a crankshaft journal that is not a perfect circle?
• The VIN (Vehicle Identification Number) identifies the model year, manufacturing plant, and ______ number.
• Vehicle alignment will not correct Pinion angle.
• If a battery with a built-in hydrometer has a green indicator, it means that the charge is full.
• Which foundation brake component requires chassis grease for proper lubrication?
• Which of the following would need to be checked prior to placing a truck-tractor into service after replacing the hood?
• If some head-bolt holes in the block are filled with oil during head installation and torqued, what is most likely to occur?
• What are the most common causes of fuel injection equipment failure?
• How many pins are in a standard tractor/trailer light cord plug?
• A water-cooled engine typically has a _______ coolant pump
• Which of the following describes the correct release sequence for a Legris quick-disconnect fitting?
• A truck has insufficient air flow out of the heat and defrost ducts. The fan is operating properly. The most likely cause would be
• The flare angle of a JIC flare fitting is 37 degrees. Which option lists the flare angle correctly?
• Excessive pressure entering the coolant system might be caused by a defective
• What should be done first to find the cause of a misfire on a diesel engine?
• Valve lash is defined as the clearance between which parts when the valve is closed?
• Valve lash is necessary to allow for
• An engine cranks normally, but will not start and shows no smoke. The most likely cause would be
• When operating high-pressure cleaning equipment, always wear safety glasses and
• Caster is the
• In the acetylene torch start sequence, what action comes immediately after turning on acetylene?
• Why is the exhaust valve lash generally greater than the intake valve lash?
• What device consists of a cylindrical rod running the length of the engine block with several oblong lobes that operate various valves?
• Which condition is most commonly responsible if a truck moves with the clutch fully depressed?
• If the torquing sequence for a cylinder head starts in the middle, what pattern is being followed?
• Which device is used to repair a stripped bolt hole by inserting a coil?
• To protect yourself while using high-pressure cleaning equipment, you should
• A driver has complained of a loud, bumping noise in the area of the rear cab mount when traveling on rough roads. The most likely cause of this noise would be a/an
• Rust streamers are observed below the bolts that attach the fifth wheel to the frame rail. This is the most likely caused by
• A pressurized cooling system has the advantage of which of the following?
• Which component uses a cylindrical rod with oblong lobes to operate engine valves?
• Free travel at the clutch pedal refers to the distance the pedal travels before which event occurs?
• When using oxyethylene torch equipment, what should be done with the acetylene regulator pressure?
• Which wrench is specially made for tight-fitting spaces such as engine compartments?
• Parabolic leaf springs provide smoother riding comfort and less stiffness than which type of springs?
• Which tool is commonly used to measure the diameter of a crankshaft journal?
• By selecting a brass hammer to dislodge a part, the technician can prevent ______.
• During welding, popping sounds and pitting indicate flux impurity. Which issue is most closely associated with this condition?
• Legris quick-disconnect air brake fittings are designed to release the line by applying which two steps?
• Oily rags should be stored in a self-closing ________.
• To follow approved safety procedures, always charge a battery in a well-ventilated area.
• Which action in high-pressure fuel lines can alter the timing of fuel delivery?
• In a hydraulic disc brake system, the brake pads are pressed against the rotor by the ______
• Rust streaks observed under the fifth wheel bolts are most commonly caused by which issue?
• A pyrometer is a useful instrument for checking _______ in a diesel engine.
• Upon initial startup of a serviced engine, what should be checked?
• If lights were wired in parallel and one bulb burns out, the other bulb will
• Which component controls the air compressor cut-in pressure?
• Which tool is used to check flywheel face runout?
• If an air compressor is not unloading when reaching normal cut-out pressure, the cause could be a
• When checking the inside of the cab during a preventive maintenance inspection, the air compressor cut-in pressure is observed to be 75 psi. What would be the most likely cause of this problem?
• What should be done before starting the engine after installing a new fuel filter?
• If grease is seen pushing past the trunnion seals on three of the four crosses during universal joint maintenance, what action is indicated?
• MSDS stands for
• A truck is involved in a accident with a offset impact to the frame. What type of damage is most likely to result from this type of impact
• The primary purpose of a turbocharger is to
• An equalizing or walking beam distributes weight evenly to
• Which condition is indicated by the frame damage pattern described as a diamond shape after an impact?
• What procedure helps preserve alignment when replacing a tie rod end?
• Which step follows lighting with striker in the acetylene torch start sequence?
• On heavy truck steer axles, _______ are used to secure the leaf springs to the axle beam.
• A driver reports that the truck continues to move even when the clutch is fully depressed. The most likely cause is
• Crankshaft main and connecting rod journals are measured for diameter, out-of-round, and which other dimensional characteristic?
• What is the proper way to secure a part in a bench vise that might be damaged from the vise teeth?
• Excessive preloads in a steering gear box would result in
• Pressurized air from the turbocharger is cooled by the _______ before it enters the combustion chamber
• On a four-stroke engine, if gear A is a camshaft spinning at exactly half the speed of gear B, then B is a/an
• The sealing lip on a wheel seal must face which direction?
• What is the acceptable free travel range for the clutch pedal on a Spicer double plate clutch?
• Bearing crush is a manufacturing concept used to ensure
• When the ignition switch is turned to the start position, you hear a single click and the engine does not turn over. What is the most likely cause?
• The primary cause of low coolant temperature in a diesel engine is
• The distance that the piston moves from BDC to TDC is
• Oil in the hose between the turbocharger and the intake manifold indicates
• When replacing leaf springs, which hardware should be replaced at the same time?
• When turning the ignition to start, a loud grinding sound is heard and the engine does not turn over. The most likely cause is
• Check coolant SCA (supplemental coolant additives) level
• Which condition in the fuel system is most likely caused by a restricted fuel filter?
• What is the typical specified free travel for a manually adjusted S-cam slack adjuster?
• In electrical diagrams, the ground symbol indicates a connection to the reference ground.
• The U.S. DOT requires a cab to contain a fire extinguisher and _______ for emergency safety.
• When the brake pedal is depressed by the driver, the _______ applies hydraulic pressure to the brake system.
• In a typical alternator charging system, the rectifier's function is to
• To safely lift a diesel engine, use a/an
• In oil coolers, the hot oil transfers its heat
• Which ignition type describes most diesel engines?
• If the wheel seal lip is installed facing away from the fluid, the seal is
• Which component transforms pedal action into pressurized brake fluid in a hydraulic brake system?
• Which pedal height corresponds to the throw-out bearing contacting the clutch brake in a non-synchronized Spicer double plate clutch?
• When measuring maximum thickness variation of a disc brake rotor, the technician should use a/an
• When removing a tie rod end for replacement, the technician should
• In the context of end-gap measurement, which type of ring is specified for the measurement?
• For the Spicer double plate clutch with a non-synchronized transmission, the correct pedal height where the throw-out bearing contacts the clutch brake is
• To check a cylinder head for twist and warpage, which tools are used together?
• A high-rate discharge test should use a load that is _______ the CCA rating of the battery.
• Valve lash is necessary to allow for
• If the camshaft turns at half the speed of the crankshaft, what is the crankshaft when compared to the camshaft?
• One complete revolution of the thimble on an English micrometer corresponds to how many inches?
• Pop testing a nozzle is used to determine
• If the top of the tire tilts outward, it has positive camber.
• Which of the following statements about Teflon tape application to pneumatic fittings is correct?
• An equalizing or walking beam distributes weight evenly to
• In an air brake system, the low pressure warning light and buzzer must activate at all pressures of _______ or below
• If the original crankshaft diameter range is 3.499 to 3.500 inches and material is removed by 0.005 inches, what is the new diameter range?
• When performing a PMI on the frame and suspension, a spring pin will not take grease with the vehicle weight removed from the suspension. The technician should next perform what step?
• The part of the starter that spins the drive is known as the
• Small electric heaters called _______, are placed in the combustion chambers of some diesel engines to help with cold starts
• When using any type of fire extinguisher, the correct method is to
• What device may be used to repair a bolt hole that has been stripped out and is unable to be re-tapped?
• The operator of a diesel truck has a complaint of low power and no smoke. the technician should first check the
• Over-inflation of a tire will cause excessive tire wear on the ______ of the tread.
• Positive camber is characterized by which condition of the tire?
• Measure ring-end gap with a/an ______ ring.
• A restricted air filter in a diesel engine will most likely cause which of the following?
• Which of the following causes galvanic corrosion between frame members?
• What is Plastigage used to check?
• In an air disc brake assembly, the outboard brake pad lining is forced against the rotor friction surface by _______ movement
• Which device is used to measure resistance?
• What instrument is used to measure caster on a straight beam steering axle?
• The air governor should cut out between which pressure range?
• Coolant SCA level should be checked
• Which item is not a measurement used for crankshaft journals: Diameter, Out-of-round, Taper, Color?
• Which of the following foundation brake parts should be lubricated with chassis grease?
• A diesel engine will produce excess amounts of nitrogen oxides (NOx) when
• The two long main components of the chassis frame are called the
• The exhaust valve dissipates its heat through the
• Which symptom indicates oil seal leakage in the turbocharger system?
• During rotor inspection, which instrument would you use to assess runout and thickness variation?
• Which of the following components would most likely be used to supply power to a circuit with high current flow?
• A breaker bar's longer length increases what quantity when applying the same force?
• Which tool is most appropriate for verifying the internal diameter of a bore to check wear?
• Engine operating temperature is regulated by the
• During a compression test, a low cylinder plus air heard from the dipstick indicates
• When a camshaft is located below the cylinder head, the rocker arms are activated by
• During clutch adjustment on a Spicer double plate clutch with a non-synchronized transmission, the throw-out bearing should contact the clutch brake when the pedal is how far from the floor?
• On a truck equipped with air brakes, the parking brakes are held on (applied) by what mechanism?
• What device is used to remove air from a hydraulic brake system?
• The two C-shaped longitudinal components of a truck frame are called the
• The proper tools to check the vertical king pin movement on a heavy truck is a/an
• What is the first act of troubleshooting an air system problem?
• If a crankshaft originally measured 3.499 to 3.500 inches and is machined by removing 0.010 inches, what is the resulting diameter range?
• When using an acetylene cutting torch, how should the flame appear?
• When drilling a hole in a piece of metal, the technician uses a center punch to
• New cab and chassis components used to replace damaged or worn components are known as a
• Center punch is used to
• Electric current is measured in what units?
• The viscosity rating of an oil indicates the
• If battery acid gets in the eyes the FIRST action should be to
• Which tool combination is used to check cylinder head for twist and warpage?
• What instrument is used to measure wear inside an engine cylinder?
• In the block, the oil spray tubes cool the
• When testing a diode with an ohmmeter, reversing leads yields which result?
• Which of the following can cause low oil pressure?
• A hole in the crown of a piston could be caused by______.
• The give or play in the valve train before the cam starts to open the valve is called
• Galvanized pipe is not acceptable in heavy equipment applications because its coating can come off and damage components. What coating is involved?
• The diesel engine is often is called a/an _______ ignition engine
• How many pins are in a standard tractor/trailer light cord plug?
• Cranking time in excess of 30 seconds can cause
• Why are cylinder liners generally used on diesel engines?
• Which action is appropriate if a universal joint cross shows that one bearing is not receiving lubricant during servicing?
• Excessive coolant system pressure can be caused by a defective
• Overusing ether in an engine can cause which of the following damages?
• In an air brake system, the air governor controls the cut-out pressure range.
• What component directs oil from the pan toward the pump in most engines?
• In a hydraulic brake system, air is removed from the system at the ______
• Which of the following would be the most dangerous for cleaning engine parts because of its flammability?
• What is the maximum number of adapters and extensions allowed when using a 3/4-inch drive socket wrench?
• Six short lines on the head of a capscrew indicate a hardness of?
• Which is the proper sequence to start an acetylene cutting torch?
• When performing the flywheel runout check, the dial indicator base is secured to the flywheel housing and the pointer rests on which surface?
• Bearing crush provides
• MSDS stands for
• Which angle is used for JIC hydraulic fittings flare?
• Before lubricating oil in the pan enters the oil pump, it passes through the
• Which adjustment should be checked after hood replacement to ensure proper visibility?
• Spilled battery electrolyte should be neutralized with a solution of water and which substance?
• Which condition would most directly cause a diesel engine to crank but not start?
• Always maintain at least _______ points of contact with hands on the grab handles and feet on the ground or steps.
• A driver has complained of a whistling noise in the cab at road speed. The noise changed with road speed and is not affected by engine load or speed. The most likely cause would be a/an
• While lubricating a universal joint cross, grease is seen pushing past the trunnion seals on three of the four crosses. This indicates which of the following?
• To get an accurate caster measurement on a straight beam steering axle, the technician should place the vehicle on a level surface and use a
• Where should the dial indicator pointer be placed when checking flywheel face runout?
• Which term describes new cab and chassis components used to replace damaged or worn components?
• A _______ is used to reduce road shock and support loads on a vehicle.
• In a steering system, the ______ connects the output shaft of the steering box to the drag link.
• Which symptom indicates excessive preload in a steering gear box?
• When installing a cylinder head, the torquing sequence is normally started
• Over-inflation wear occurs at which part of the tread?
• Flexible material commonly used as a bumper cover is known as the
• Before welding a chassis on a computer controlled vehicle, what should be disconnected?
• Which symptom is most closely associated with a defective thermostat in the cooling system?
• A diode conducts in one direction and blocks in the other due to its directionality.
• Oil spray tubes in the engine block are designed to cool which area?
• At sea level, water freezes at 32 degrees Fahrenheit and boils at what temperature?
• A breaker bar, with its additional length, generates more _______ than using a standard wrench with the same amount applied force.
• The symptom of a whistling noise in the cab that is caused by a misadjusted component is most likely due to which of the following?
• Which component regulates engine temperature by opening to allow coolant flow when the engine is hot?
• Nylon and plastic tubing size is stated in terms of
• What does the term 'out-of-round' describe in crankshaft journals?
• The maximum allowable run out on cast spoke wheels is which value?
• The timing of fuel delivery can be altered in high-pressure fuel lines by
• If battery acid gets in the eyes, the FIRST action should be to
• Shock absorbers use which kind of gas for better damping?