SOS Mechanic Certificate – Engine Repair Practice Exam

These questions are part of the practice quiz. Start practicing

• What might be a cause of excessive exhaust smoke?
• What is the purpose of a timing belt in an engine?
• What is likely indicated if a mechanic observes drops of oil seeping from the oil pan?
• What is the function of a fuel pump in an engine?
• What can cause an engine to overheat?
• If rod journal surfaces are smooth and show no taper, what should you do next?
• What is the function of the exhaust manifold in an engine?
• What is the function of the camshaft in an engine?
• Which component is responsible for circulating coolant in the engine?
• What symptom indicates a faulty thermostat?
• How is the engine oil level typically checked?
• What is a common cause of insufficient fuel delivery to the engine?
• What is the typical valve-tappet clearance on a running engine with hydraulic lifters?
• Which component is responsible for drawing in air and fuel into the engine?
• What could cause engine knocking?
• What is the role of a camshaft in an engine?
• What is the primary function of a thermostat in an engine?
• What are piston rings used for in an engine?
• What should a mechanic do if the piston rings bind on the block surface?
• To find the amount of bore taper, which calculation should be performed?
• How do fuel injectors function in an engine?
• Which of the following measurements is relevant when assessing bore taper?
• What troubleshooting steps should be taken for an engine that will not start?
• During a manifold vacuum test, the vacuum gauge needle registers a steady 12 inches at idle. Which one of the following would cause this?
• What is primarily involved in an engine rebuild?
• Which one of the following is not a recommended break-in practice for an overhauled engine?
• What should short pieces of hose be used to protect when assembling an engine?
• What is meant by the term "engine misfire"?
• What is the primary function of fuel injectors in an engine?
• Which of the following is a consequence of excessively worn valve guides?
• What does the presence of intake valve deposits typically indicate?
• What could cause a large build-up of sludge in the crankcase of an engine?
• What is a key difference between a timing chain and a timing belt?
• What is the main purpose of an engine's cooling system?
• What is the correct procedure for adjusting valve tappet clearance?
• What is the first step in replacing an engine water pump?
• What is the primary purpose of the intake manifold in an engine?
• What may cause sputtering during acceleration in a vehicle?
• What adjustment might be needed if an engine is idling too high?
• What could cause a decrease in engine performance related to fuel delivery?
• What is the purpose of diesel glow plugs?
• Which one of the following will cause oil consumption?
• What does an engine misfire indicate?
• What is the proper way to install camshaft bearings?
• What could indicate a problem with fuel injectors?
• What is the most likely cause of low oil pressure in a warm engine?
• What is a key difference between synthetic and conventional oil?
• What are the potential consequences of running an engine without coolant?
• What is the role of an ignition coil?
• What is one of the purposes of an oxygen sensor in a vehicle?
• What is a potential result of a malfunctioning oxygen sensor?
• During a cylinder leakage test, what does airflow out of the throttle body indicate?
• Why is coolant important in an engine?
• What is one consequence of allowing an engine's timing to remain off over time?
• What might be a consequence of using the incorrect fuel octane rating?
• What does a check engine light typically indicate?
• What typically indicates a cooling system leak?
• What is the purpose of replacing the gasket when installing a new water pump?
• When replacing an engine water pump, what should be done after draining the coolant?
• Which component is crucial for air control during combustion in an engine?
• Which process should be followed to diagnose an overheating engine?
• What main role does the exhaust manifold serve in an engine?
• What does engine revving indicate?
• What does valve guide wear affect in an engine?
• What are the minimum and maximum measurements of a shaft given 2.125 plus or minus .015?
• What is a potential effect of a higher octane fuel?
• How does an engine use compression?
• What method can a mechanic use to inspect the fuel system for blockages?
• What tool is commonly needed to detach the engine water pump?
• Too much crankcase blow-by is likely caused by:
• What impact does a clogged catalytic converter have on engine performance?
• What can be a result of a fuel filter that has not been replaced regularly?
• What is a common effect of worn bearings in an engine?
• During the break-in period, how should engine speed be managed?
• When is it typically necessary to replace a timing belt?
• What is the purpose of the timing belt in an engine?
• What happens to the exhaust gases in a catalytic converter?
• What function does a spark plug serve?
• Why is it important to drain the coolant before replacing the water pump?
• After refacing a valve and recutting the valve seat, how can you compensate for the change in valve spring height?
• What potential issue arises if an engine runs too lean?
• How can carbon deposits affect engine performance?
• After measuring the cylinders and finding them to be smooth and pistons reusable, what is the next step?
• Why is it important to check the top ring groove for wear after cleaning?
• What does a torque wrench do?
• When is the best time to check for crankshaft endplay?
• Which of the following can lead to low engine oil pressure?
• After machining the cylinders, you would hone the bores to:
• What is the main purpose of the throttle body in an engine?
• How often should engine oil be changed for optimal performance?
• What is engine surging?
• How can a mechanic determine if a valve adjustment is needed?
• What condition might cause a rattling noise from the engine?
• How can excessive camshaft lobe wear be determined without removing the cam from the engine?
• In a turbocharged vehicle experiencing low power, what could be a potential cause?
• During a compression test, what must be done with the throttle and choke?
• What is a commonly used material for piston rings in today’s overhauled engines?
• Which component must be disconnected when removing a transverse-mounted engine and transaxle as a unit?
• What should the margin be when grinding an exhaust valve?
• What collection does the exhaust manifold provide from the engine cylinders?
• During a pre-purchase engine assessment, what should you check for?
• What are common signs of a failing alternator?
• Which component is crucial to check for movement during a compression test?
• What effect does a failing water pump have on an engine?
• Which option describes a SAE Grade 5 bolt?
• How often should engine oil typically be changed?
• What does a smooth rod journal surface indicate?
• How can you determine if an engine is not firing on all cylinders?
• What is the primary role of the oil filter?
• What defines an engine block?
• In what situation would a mechanic want to degrease cylinders?
• What role does the fuel filter play in an engine?
• What are common symptoms of a failing head gasket?
• What function does a rocker arm serve in an engine?
• What symptom indicates the need for immediate diagnostic checking of the engine?
• What should you check if an engine is having difficulty starting?
• When should engine oil generally be changed for optimal performance?
• Which component can significantly affect the electrical system while driving?
• Which of the following can reduce engine performance?
• What is required if a camshaft is worn beyond specifications?
• What is the purpose of valve-tappet clearance?
• If two middle cylinders of a V-8 engine show low compression readings of 50 PSI while others read between 135 and 140 PSI, what is the likely cause?
• What likely causes bubbles to form in the coolant when the radiator cap is removed and the engine is running?
• What is important when determining the ring end gap for a cylinder with a 3-inch bore?
• Which of the following actions is most detrimental during the break-in of an overhauled engine?
• What effect does increased engine temperature have when running too lean?
• What is the role of engine oil during the break-in period?
• Pistons for a V-6 engine are generally:
• What are common symptoms of a faulty head gasket?
• If a 0-1 inch micrometer reads 5.750 inches, what should the correct reading be?
• What is the function of a catalytic converter?
• What might cause an engine to backfire?
• What is the function of engine oil in a vehicle?
• What are common causes of engine overheating?
• Why is the compression ratio important in an engine?
• What should be replaced along with the new water pump?
• How does an EGR valve function?
• What is a PCM (Powertrain Control Module)?
• How does a turbocharger enhance engine performance?
• What does a check engine light typically indicate?
• How does an engine rev respond when power is needed?
• How long should an overhauled engine typically be allowed to idle with no load during the break-in period?
• What type of tool is used to measure valve clearance?
• Which action is taken last during the water pump replacement process?
• How does an internal combustion engine produce power?
• What does 're-torqueing' cylinder head bolts do?
• What is the primary purpose of the break-in process for a newly overhauled engine?
• What maintenance task is typically required for fuel systems?
• How can you identify a vacuum leak in an engine?
• What is the approximate ring end gap required for a 3 inch bore cylinder?
• What role does the ECU play in an engine?
• What can a vacuum leak cause in an engine?
• When should piston rings be checked for fit?
• What should be done if an engine shows signs of low oil pressure?
• What typically controls the valve timing on most engines?
• What is likely to happen if the cooling system in an engine fails?
• What effect does running an overhauled engine at full load during the break-in period typically have?
• How can a technician confirm a new water pump has been installed correctly?
• What aspect of a valve spring is typically being checked using an illustration?
• How does the engine's temperature affect its performance?
• What would you expect to happen if you have ignition problems in an engine?
• What does "blow-by" refer to in an engine?
• How does engine displacement affect performance?
• Which component mainly synchronizes engine timing without the need for maintenance?
• What might cause excessive exhaust smoke in an engine?
• What tool is best to use for measuring wear in the top ring groove of a piston after cleaning?
• When using a vacuum gauge connected to the intake manifold, what occurs when the engine is rapidly accelerated?
• What should be monitored closely after an engine overhaul during the break-in stage?
• How is valve concentricity measured?
• What is the purpose of an air filter in an engine?
• Which diagnostic tool is commonly used to read trouble codes from the engine control unit (ECU)?
• Which of the following should be monitored to ensure proper engine function?
• What action should be taken when there are signs of oil leaks in an engine?
• What could be a reason for an oil leak in an engine?
• What should be checked during a routine engine inspection?
• What is the first step in the process of replacing spark plugs?
• What is the significance of engine compression testing?
• If the fan blade tips of a water pump mounted fan move between one-eighth and one-quarter inch back and forth, what does this indicate?
• What should one ensure about the water pump before operating the engine?
• When examining bearing inserts using plastigage, if Insert "A" has more clearance, what does this indicate?
• The function of an engine's crankshaft is primarily to?
• How do compression rings function within an engine?
• Within what temperature range is normal engine operating temperature typically found?
• Rod journal out-of-round is the difference between the journal measurements at:
• What is the purpose of a timing chain in an engine?
• How often is it recommended to check your engine coolant?
• What is a crankshaft?
• Which of the following could indicate a carburetor issue within an engine?
• What does "engine tuning" refer to?
• Which symptom is NOT typically associated with an engine's timing being off?
• What is the primary function of a radiator in an engine cooling system?
• Which of the following is a key sign of a failing fuel pump?
• What is one common symptom of a blown head gasket?
• What is the primary function of a timing belt in an engine?
• Which one of the following will not be affected when replacing piston #1 with piston #2?
• When reinstalling pistons with new rings, what should you do if the ring compressor does not fit tightly around a piston skirt?
• Which direction should the trademarks or dots on piston rings face during installation?
• How can crankshaft endplay be checked?
• A bore gauge is primarily used to measure which aspect of cylinders?
• If hydraulic lifters are noisy at highway speeds but quiet at low speeds, what should you check first?
• Which tool is commonly used to torque main bearing caps?
• What is a key indicator that an engine’s timing may be incorrect?
• What effect does a faulty spark plug typically have on engine performance?
• What could lead to an engine stalling?
• Which of the following are common signs of a failing alternator?
• What are common signs of an oil leak?
• What is engine knock detection designed to monitor?
• What could be the cause for no fuel squirting into the carburetor when the throttle is opened quickly?
• What is a potential consequence of not allowing for proper engine break-in?
• What does an oil pressure gauge indicate?
• Which component is most crucial for ensuring proper sealing in an engine during initial operation?
• What is the primary purpose of engine oil?
• What is an effect of using low-quality fuel in an engine?
• What is the purpose of an engine balance shaft?
• What could a malfunctioning spark plug result in?
• What can be determined from a plastigage on a bearing insert?
• What fluid is typically used for a car's cooling system?
• What is the function of piston rings in an engine?
• A mechanic is checking main bearing clearance with plastigage. If the plastigage flattens more at one end than the other, it would indicate:
• What can cause engine knock or pinging?
• What is the primary purpose of an engine air filter?
• Before installing the pistons in a newly honed cast iron block, you should clean the bores with:
• What is one common reason for an engine to backfire?
• After how long should the engine oil typically be changed post-break-in?
• What does a consistent dimming of lights often signify in a vehicle?
• What is generally the best practice regarding engine oil during the break-in period of a new engine?
• What does valve clearance refer to?
• How does a mass air flow sensor function?
• What sound might indicate a problem with a fuel injector?
• What issue can a faulty fuel pump cause in an engine?
• What could leaking coolant indicate?
• What does it indicate if oil appears milky on the dipstick?
• In which scenario might an engine exhibit rough running?
• What does a low oil pressure warning indicate?