Engine Repair A1

Technician A says if a timing belt is removed and is going to be reused, the direction of rotation must be marked. Technician B says a timing belt that has been contaminated with oil can be cleaned and reused. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. A used timing belt that is removed and will be reused must be put back on in the same direction of rotation it came off; failure to do this may cause belt failure. Answer B is incorrect. A timing belt that has been contaminated with oil will deteriorate and fail. If it is cleaned, the oil that has saturated the belt will not be removed. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

The customer complains of a loud thump when he accelerates from a stop. Technician A says it could be caused by worn crankshaft thrust bearings. Technician B says it could be caused by a cracked flexplate. Who is correct? A A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. Excessively worn thrust bearings will allow the crankshaft to shift forward during acceleration, causing a thump when the crankshaft comes up against the main bearing thrust surface. Answer B is incorrect. A cracked flexplate will typically sound like a sharp pop or knock as it flexes at the crack. Answer C is incorrect. Only Technician A is correct. rivens or badbart Answer D is incorrect. Technician A is correct.

Technician A says that o-ring type valve stem seals are installed after the spring and retainer are installed. Technician B says that positive lock valve stem seals ride on the valve stem. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. O-ring type valve stem seals seal the spring retainer to the valve stem and are installed after the spring and retainer are installed and the spring is compressed. Answer B is incorrect. Positive lock valve stem seals are press fit onto the valve guide and the valve rides up and down through it. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

Technician A says some manufacturers use a sensor to indicate air filter condition. Technician B says air filter condition is displayed on the dash. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. Some manufacturers us an air filter condition sensor in the air intake ductwork. As airflow is reduced by a dirty air filter, the sensor changes from green to red. Answer B is incorrect. The air filter sensor is not an electrical input on the dash display. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

An engine miss is being diagnosed using a cylinder leakage test. Technician A says that a 20 percent leakage is acceptable. Technician B says air coming out the intake manifold indicates a cracked cylinder head. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. The acceptable leakage from a cylinder is 20 percent. This allows for normal leakage past ring end gaps. Answer B is incorrect. Air coming out the intake manifold indicates leaking intake valves. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

While performing a cranking compression test on a 4-cylinder engine, the technician notes that one cylinder has a pressure reading of 60 psi, 44 kPa, while the others have a reading of 135 psi, 931 kPa. Technician A says performing a cylinder leakage test will indicate where the pressure is leaking. Technician B says the vehicle has worn valve guides. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. The next step for narrowing down the cause for low compression on one cylinder would be the cylinder leakage test. Answer B is incorrect. Worn valve guides will not cause a loss of compression. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

Technician A says that a worn valve guide should be reconditioned or replaced before the valve seats are reconditioned. Technician B says the valve seats should be replaced before repairing the valve guide. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. Only Technician A is correct. Valve guides should be repaired first. The valve guide serves as the center of the seat during reconditioning. Answer B is incorrect. The valve guide should be repaired first as it is used as the center point for seat replacement or reconditioning. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

Which of these should be performed first when a starter fails to crank the engine? A. Measure static battery voltage. B. Remove and check spark plugs. C. Check for fuel pressure. D. By-pass the starter solenoid with a remote starter button.

Answer A is correct. The battery voltage should be checked first to verify there is enough power to turn the starter. Answer B is incorrect. Spark plugs may be removed if a hydro-lock condition is suspected in the cylinder. This would not be the first test. Answer C is incorrect. Fuel pressure that is not at specifications may cause an engine to not start but will not keep it from cranking. Answer D is incorrect. The correct battery voltage should be checked first. The solenoid can be by-passed if there is a faulty ignition switch or neutral safety switch.

Technician A says an intercooler may be used to cool the air taken in by the supercharger before it reaches the combustion chamber. Technician B says it is to prevent the supercharger from overheating. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is correct. The intercooler reduces the heat content of the air from the supercharger before it enters the combustion chamber. Answer B is incorrect. The intercooler does not cool the supercharger. Answer C is incorrect. Only Technician A is correct. Answer D is incorrect. Technician A is correct.

The customer complains of a loud noise coming from the engine compartment. Which of the following would be the LEAST LIKELY to cause the noise? A. Cracked exhaust manifold B. A vacuum leak C. A cracked flexplate D. Carbon buildup on the pistons

Answer A is incorrect. A cracked exhaust manifold would cause a cracking or rumbling noise when cold. Answer B is correct. A vacuum leak would typically not cause a loud noise that the customer could hear from inside the car. A vacuum leak would be a high-pitched whistle. Answer C is incorrect. A cracked flexplate would create a loud snapping or knocking noise at idle which might diminish as speed increased. Answer D is incorrect. Carbon buildup on the pistons will cause a knocking noise from the affected cylinder.

During a power balance test on a port fuel-injected engine, one cylinder is found to have virtually no RPM change. Which of these is the most likely cause? A. A faulty crankshaft position sensor B. A vacuum leak at the throttle body C. A defective plug wire D. A faulty camshaft position sensor

Answer A is incorrect. A faulty crankshaft position sensor will affect all cylinders rather than just one. Answer B is incorrect. A vacuum leak at the throttle body will affect all cylinders. Answer C is correct. If the plug wire on that cylinder is defective, the cylinder will not fire and contribute to power. Answer D is incorrect. A faulty camshaft position sensor would affect all cylinders.

Which of the following tools would be used to measure valve-to-guide clearance? A. A micrometer and feeler gauges B. A dial caliper and feeler gauges C. A feeler gauge and machinist's rule D. A small hole gauge and a micrometer

Answer A is incorrect. A feeler gauge is not suitable for this measurement. Answer B is incorrect. A feeler gauge is not suitable for this measurement. Answer C is incorrect. A feeler gauge is not suitable for this measurement and a machinist's rule is not a suitable measuring tool for this small of a measurement. Answer D is correct. A small hole gauge is used to transfer the guide diameter to a micrometer for the measurement.

The vehicle has an intermittent no-crank condition; the starter relay has been replaced Which of the following is the LEAST LIKELY cause? A. Loose connection at the battery B. Worn neutral safety switch C. Open circuit in the battery positive wire on the starter D. Worn ignition switch

Answer A is incorrect. A loose connection at the battery may provide current flow intermittently. Answer B is incorrect. A worn neutral safety switch may cause intermittent contact. Answer C is correct. An open circuit in the battery positive wire on the starter will ca no-crank condition all the time. Answer D is incorrect. A worn ignition switch contact may provide intermittent continuity.

The technician has done a compression test on an engine and found cylinders #1 and #3 to have low compression. What would be the next test he should do in his diagnosis? A. Power balance test B. Cylinder leakage test C. Wet compression test D. Dynamic compression test

Answer A is incorrect. A power balance test would not be done. He is looking for a mechanical failure, not an ignition or fuel failure. Answer B is incorrect. A cylinder leakage test may need to be done but it is not the next test. Answer C is correct. A wet compression test will indicate whether the loss of compression is through the rings or somewhere else. Answer D is incorrect. A dynamic compression test checks for proper breathing in an operating engine and would not be the next test.

An engine idles rough and the technician notes a high-pitch whistle from the engine compartment. Which of the following would most likely be the cause? A. A slipping fan belt B. A leaking exhaust pipe C. A defective alternator bearing D. A vacuum leak on the intake

Answer A is incorrect. A slipping fan belt will squeal, not whistle. Answer B is incorrect. A leaking exhaust manifold will make a popping noise or rumbling. Answer C is incorrect. A defective alternator bearing will growl. Answer D is correct. A vacuum leak on the intake can cause a rough idle if it is after the airflow meter. Due to unmetered air entering the engine, it will cause a high-pitch whistle as the air is drawn into the engine.

Technician A says a full-floating piston pin will ride in a steel bushing in the small end of the connecting rod. Technician B says a bronze bushing is used. Who is correct? 100A A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. A steel bushing is not used. Answer B is correct. Only Technician B is correct. A bronze bushing is used because of its good lubricating properties. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

The technician is investigating an intermittent popping noise from under the hood that occurs when the RPM is raised. Which of the following is the LEAST LIKELY cause for the noise? A. Sticky intake valve B. Incorrect ignition timing C. Broken intake valve spring D. Worn rod bearing

Answer A is incorrect. A sticky intake valve that is slow to close may be open enough to allow combustion to escape before it closes all the way. Answer B is incorrect. If ignition timing is off, the spark may occur before the intake valve is completely closed allowing combustion to escape. Answer C is incorrect. A broken or weak intake valve spring will not close the intake valve rapidly enough, or not at all, allowing combustion to escape. Answer D is correct. A worn rod bearing noise would be constant and increase in frequency as the RPM is raised.

A high-mileage vehicle overheats only at highway speeds. Which of the following is the most likely to be the cause? A. A stuck closed thermostat B. A defective radiator cap vacuum valve C. An inoperative cooling fan D. A radiator whose core is clogged with deposits

Answer A is incorrect. A stuck closed thermostat will cause overheating in city or low-speed driving. Answer B is incorrect. A radiator cap vacuum valve should only function during cooling off periods with the engine off. Answer C is incorrect. At highways speeds, the cooling fan function may be replaced by ram air effect. Answer D is correct. At highway speeds, the heat produced in the engine is greater. If the radiator cannot transfer that extra heat to the core because of blockage, it will cause engine overheating.

Which of the following could cause symptoms of overheating even though the engine temperature is normal? A. A stuck closed thermostat B. A defective radiator cap C. A defective temperature sending unit D. A missing thermostat

Answer A is incorrect. A stuck closed thermostat will make the engine actually overheat. Answer B is incorrect. A defective radiator cap may cause an actual overheat condition. Answer C is correct. If the temperature sending unit has gone bad, it can cause the gauge to register an overheat condition when, in fact, the engine is at the normal operating temperature. Answer D is incorrect. A missing thermostat will cause engine overcooling

All of the following are symptoms of a stuck open PCV valve EXCEPT: A. Rough engine idle. B. A lean air/fuel ratio. C. Blowby gases in the air filter. D. The engine stalling.

Answer A is incorrect. A stuck open PCV valve allows unmetered air delivery to the intake. Answer B is incorrect. A stuck open PCV valve allows unmetered air into the intake, which will lean out the air/fuel mixture in one or more cylinders. Answer C is correct. A stuck open PCV valve will not cause blowby gases in the air filter: a stuck closed valve may. Answer D is incorrect. A stuck open PCV valve allows unmetered air into the intake, which may lean out the air /fuel mixture to the point it is unburnable.

A technician begins his diagnostic procedure to repair a vehicle. Which of the following would be the LEAST LIKELY steps he would take? A. Road test the vehicle. B. Question the customer for more information regarding the problem. C. Make sure the original complaint is fixed. D. Start with the most difficult tests.

Answer A is incorrect. A technician should test drive the vehicle to verify the complaint. Answer B is incorrect. It is good practice to question the customer to get all the information regarding the problem that he can provide. Answer C is incorrect. The original complaint must be fixed to ensure customer satisfaction. Answer D is correct. During diagnosis, the technician will start with the simple and work his way through to the difficult tests. Most of the time the problem will be diagnosed and corrected before he gets to the difficult tests.

Technician A says a thermostat rated 180 degrees is fully open at that temperature. Technician B says the thermostat begins to open at 180 degrees. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. A thermostat rated at 180 degrees begins to open at that temperature. Answer B is correct. Only Technician B is correct. A thermostat rated at 180 degrees begins to open at that temperature and is fully open at about 220 degrees. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

A poor performing engine has a cranking compression test done. The test fails with all cylinders showing low compression. The technician did a wet compression test and all cylinders increased substantially. Technician A says the wet compression test results indicate the head gasket is not sealing. Technician B says the wet compression test results indicate cylinder and ring wear. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. A wet compression test is used to check for ring and cylinder wear and will not indicate anything about the head gasket condition. Answer B is correct. Only Technician B is correct. A substantial increase in compression during a wet compression test indicates worn rings and cylinder bores. The oil temporarily seals the rings on the cylinder, wall increasing compression. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

After a cold start, the customer notes a loud cracking or popping noise from the engine that quiets as the engine warms up. Technician A says this may be caused by a worn rod bearing. Technician B says this may be normal engine noise caused by lifter bleed down. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. A worn rod bearing will make a deep knocking noise, not cracking or popping, and the noise would not go away. Answer B is incorrect. Lifter noise on cold starts is a light rattle noise. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. The noise is most likely caused by a cracked exhaust manifold or manifold gasket. The noise may go away after warm up as the metal expands.

Technician A says that all coolants are the same if they are ethylene glycol-based. Technician B says different coolant types can be mixed with no problems. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. All automotive coolants used by OEM manufacturers are ethylene glycol-based. The additives in each type, which may be designated by color, are different. Answer B is incorrect. If different types of coolant formulas are mixed, the protection will be lowered and the mixture may cause gelling in the cooling system. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. Although all OEM automotive coolants are ethylene glycol-based, the additive package is different. Manufacturers determine which additives will give the best protection and long life for their engines. The different additive packages are indicated by dye added to the coolant. Some of the different additive packages are not compatible and may cause reduced protection if mixed together. It is always best to use OEM recommended coolant.

The exhaust on a customer's car is white and has a sweet smell. Technician A says this indicates a rich condition in the cylinder. Technician B says this indicates oil being burned in the cylinder. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. An engine that is running too rich will have black exhaust. Answer B is incorrect. Oil burning in the cylinders will cause the exhaust to be bluish. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. White color exhaust accompanied by a sweet smell indicates coolant is entering the cylinder.

Which of the following is the LEAST LIKELY location for an engine oil leak? A. Oil pan gasket B. Valve cover gasket C. Oil pressure sending unit D. Upper intake manifold gasket

Answer A is incorrect. An oil pan gasket is a common place for an oil leak. Answer B is incorrect. Valve cover gaskets are common locations for oil leaks. Answer C is incorrect. A defective oil pressure sending unit is a common leak point. Answer D is correct. The upper intake manifold gasket does not carry oil through it; this would not be a location for an oil leak.

The engine cranks but will not start. Which of the following is not a requirement for the engine to start and run? A. Compression B. Oil pressure C. Fuel pressure D. Spark

Answer A is incorrect. Compression is required for an engine to start. Answer B is correct. Oil pressure is developed when the engine starts running. Answer C is incorrect. Fuel pressure and delivery is required for an engine to start. Answer D is incorrect. Spark is required to ignite the fuel.

When inspected, the crankshaft bearings that exhibit more wear on the bearings the furthest from the oil pump, which is less noticeable as you get closer to the oil pump. What is the most likely reason for the wear? A. Engine overloading at low RPM wersm ai nei B. Over-tightened accessory belts C. Dry starts D. A warped crankshaft

Answer A is incorrect. Engine overloading would cause wear on all the lower main bearings. Answer B is incorrect. Wear from over-tightened accessory belts would start at the top of main bearing #1 and transfer to the lower bearing on the last journal. Answer C is correct. A condition known as dry starts occurs when the engine has not been operated in a while. If there is no oil on the main bearing surfaces and during start up, the last journal to get oil pressure will show more wear. Answer D is incorrect. A warped crankshaft will usually show up as excessive wear on one or two of the center main bearings.

11. An engine cranks over very slowly and may not start. Which is the LEAST LIKELY cause? A. Excessive electrical resistance at the starter B. Weak battery C. Broken timing belt D. Worn ignition switch contacts

Answer A is incorrect. Excessive electrical resistance may reduce the current flow to the starter causing slow cranking speed. Answer B is incorrect. A weak battery may not supply enough current to spin the starter rapidly. Answer C is correct. A broken timing belt will cause rapid crank speeds since no compression is being developed and causing a no-start condition. Answer D is incorrect. Worn ignition switch contacts may prevent no, or poor, current flow to the starting circuit.

Technician A says that fuel injectors are controlled by the crankshaft position sensor. Technician B says a noid light can be used to check for injector trigger signal. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Fuel injector pulse width is controlled by the ECM, which receives a signal from the crankshaft position sensor. O Answer B is correct. Only Technician B is correct. A noid light, plugged into the injector pigtail, is used to verify injector trigger signal. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

The LEAST LIKELY cause of camshaft bind would be: A. Improperly installed bearings. B. Bore misalignment. C. Excessive bearing clearance. D. Mixed up journal caps.

Answer A is incorrect. Improperly installed bearings could cause camshaft bind. Answer B is incorrect. Bore misalignment and warp will cause camshaft bind. Answer C is correct. Excessive bearing clearance would cause oil runoff since the clearances are larger than specified, but they would not cause camshaft bind. Answer D is incorrect. Camshaft journal caps that are installed on the wrong journal can cause camshaft bind.

Technician A says the air intake duct inlet is in the engine compartment. Technician B says to check for contaminants in the inlet when checking or replacing the air filter. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Intake air should come from outside air, not the engine compartment. Engine compartment air is higher in temperature than outside air, which raises cylinder temperature. Answer B is correct. Only Technician B is correct. If the inlet is not cleaned when the filter is changed, the contaminants in it may block the new air filter. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

With a vacuum gauge hooked to the engine, rapid fluctuation of the needle, from 14-18 in. Hg, is observed; this increases with RPM. Technician A says the intake manifold is restricted. Technician B says the valve springs may be weak or broken. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Intake manifold restrictions, before the port used, may cause a higher than normal and steady gauge reading. Answer B is correct. Only Technician B is correct. Weak or broken valve springs will not close the valves properly and vacuum fluctuates rapidly. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says that most cylinder wear occurs in the center of piston ring travel. Technician B says that most cylinder wear occurs at the bottom of piston ring travel. Who correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Most cylinder wear occurs at the top of ring travel. Answer B is incorrect. Most cylinder wear occurs at the top of ring travel. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. The center of ring travel is where the least cylinder wear occurs and the bottom of ring travel will show some wear, but the top ring travel is where the most wear occurs. At the top of the cylinder, the piston is changing direction under combustion pressures, which will cause more pressure and wear at the top of ring travel.

The camshaft bore in an overhead cam engine does not use bearing inserts. Technician says if the camshaft-to-bore clearance exceeds specifications, bearing inserts could be installed to correct the problem. Technician B says the head must be replaced. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Most heads that do not use camshaft bearing inserts do not have enough clearance in the bore to additionally bore the head oversize and install bearing inserts. Answer B is correct. Only Technician B is correct. If camshaft-to-bore clearance exceeds specifications, the head must be replaced. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says that all front-wheel drive engines can be removed through the top of the engine compartment. Technician B says that some front-wheel drive vehicle engines must be removed from underneath the vehicle. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Not all front-wheel drive engines can be removed from the top. Answer B is correct. Only Technician B is correct. Some front-wheel drive engine removals require the engine and transmission to be dropped with the subframe from underneath the vehicle. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says old coolant is not hazardous and can be disposed of in the shop drain. Technician B says old coolant should be disposed of in an environmentally safe manner. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Old coolant is considered hazardous waste in most states, and it is illegal to dispose of in a floor drain. Answer B is correct. Only Technician B is correct. Old coolant should be picked up by a licensed waste disposal company and disposed of in an environmentally safe manner. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says all piston pins are press fit into the connecting rod. Technician B says some piston pins are full floating. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Only some piston pins are press fit, not all. Answer B is correct. Only Technician B is correct. Some piston pins are full-floating pins. They are held in place by lock rings in the piston. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

A defective water pump can be diagnosed by all of the following EXCEPT: A. Using a pressure tester. B. A coolant leak from the water pump. C. A grinding noise from the pump area. D. A lower than normal reading on the temperature gauge.

Answer A is incorrect. Pressure testing the cooling system may make a leak at the water pump more pronounced. Answer B is incorrect. A defective water pump inner seal will allow coolant to leak from the water pump drain hole. Answer C is incorrect. A water pump whose bearing is going bad will cause a grinding noise. Answer D is correct. A water pump will not cause overcooling; if anything, if will cause overheating.

Technician A says RV can be used to seal a throtle body injection assembly to the intake manifold. Technician B says TV is a gasket maker and should not be applied to another gasket. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. RV should not be used in applications where fuel can come in contact with it. Fuel will cause deterioration of the seal. Answer B is correct. Only Technician B is correct. RTV is made to be used by itself as a gasket. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

A technician is changing oil in a customer's vehicle and needs to know what weight oil to put in. Technician A says the weight of oil does not matter as long as it is multigrade oil. Technician B says the technician should look on the oil filler cap or in the owner's manual. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Refilling the crankcase with the wrong weight oil may cause higher than specified oil pressure and void a customer's warranty on the engine. Answer B is correct. Only Technician B is correct. Most manufacturers emboss the proper oil weight on the oil fill cap and specify oil weight in the owner's manual. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says that piston ring gap that is too wide could cause ring binding and breakage. Technician B says that piston ring gap that is too tight would cause combustion gas blowby. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Ring gap that is too wide will cause blowby. Answer B is incorrect. Ring gap that is too tight will cause binding and breakage. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. The rings should seal the cylinder as tightly as possible without binding. If the ring gap is too wide, the ring will not seal properly as it expands from heat and will have enough gap to allow excessive combustion gases (blowby) into the crankcase and result in a loss of power. A ring that has too little gap will become tight in the cylinder bore as it expands from heat causing binding on the cylinder wall, cylinder scuffing, and ring or piston damage.

While checking coolant level in the radiator, red oily specs are noted floating on the coolant. Technician A says this is rust and the system should be flushed. Technician B says this is probably transmission fluid and the cooler built into the radiator is leaking. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Rust in the cooling system will usually settle to the bottom of the radiator since it is heavier than the coolant. Answer B is correct. Only Technician B is correct. Oil floats on liquid and the red oily specs in the coolant are probably transmission fluid coming from the transmission cooler built into the radiator. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says all piston pins are centered in the piston skirts. Technician B says some piston pins might be offset. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Some piston pins are centered, others are offset from center. Answer B is correct. Only Technician B is correct. Some piston pins on V-engines are offset toward the major thrust surface to reduce piston rock under combustion pressures. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

All of the following are true about TTY bolts EXCEPT: A. Provide a more uniform clamping force. B. Usually require special tightening procedures. C. Must always be discarded after use. D. May be used in connecting rod applications.

Answer A is incorrect. TTY bolts provide more uniform clamping force. Answer B is incorrect. TTY bolts are tightened to a specified torque, then turned an additional number of degrees. Answer C is correct. TTY bolts may be reused after being checked for stretch following manufacturer's recommendations. Answer D is incorrect. TTY bolts are used in some connecting rod assemblies.

Technician A says a V-belt that is too tight can wear out water pump bearings. Technician B says that a V-belt that is too tight can cause the #1 crank journal bearing to wear out on the upper half. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A V-belt that is overtightened pulls up on the crankshaft and can cause the upper main bearing to wear out. It will also put too much pressure on one side of the water pump bearing, causing early failure. Answer D is incorrect. Both Technicians are correct.

Technician A says a cracked exhaust manifold can cause poor fuel economy. Technician B says a cracked exhaust manifold will cause incorrect oxygen sensor readings. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A cracked exhaust manifold will allow air to be drawn into the exhaust and cause the oxygen sensor to sense a lean condition, which will cause the ECM to increase fuel delivery resulting is decreased fuel economy. Answer D is incorrect. Both Technicians are correct.

Technician A says pushrods may be used to deliver oil to the rocker arms. Technician B says a bent pushrod may indicate a valve was struck by a piston. Who is correct? A. A only B. Bonly C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A hollow pushrod is used to deliver lubrication to the rocker arms from the lifter. A pushrod may be the weakest link in the valve train, so if a piston hits a valve, the pushrod may bend before the valve stem. Answer D is incorrect. Both Technicians are correct.

Technician A says that valve train related noise could be caused by a low oil level. Technician B says that valve train related noise could be caused by valves that need to be adjusted. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A low oil level will reduce the amount of oil pumped to the top of the engine, leaving the valves with no lubrication. If a valve train has excessive clearance between components, it will cause noise until corrected. Answer D is incorrect. Both Technicians are correct.

An engine overheats in stop-and-go traffic but does not overheat on the highway. Technician A says a defective radiator cap may be the cause. Technician B says an inoperative electric cooling fan may be the cause. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A radiator cap that will not hold its rated pressure will allow the coolant to boil below normal operating temperature; the resulting loss of coolant will cause overheating. A cooling fan is needed for airflow in stop-and-go traffic, but on the highway, ram air will carry the heat away. Answer D is incorrect. Both Technicians are correct.

A cranking compression test on a 4-cylinder engine has been done and the results were: CYL. #1 - 135 psi CYL. #2 - 20 psi CYL, #3 - 20 psi CYL. #4 - 130 psi Technician A says a wet test should be done on cylinders #2 and #3. Technician B says the results indicate a blown head gasket between cylinders #2 and #3. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A wet test will enable the technician to eliminate rings as a possible problem. Typically, the same low compression readings on adjacent cylinders indicate a blown head gasket. Answer D is incorrect. Both Technicians are correct.

A customer's vehicle is leaking oil on his driveway from the rear of the engine. Technician A says the leak may be coming from the rear main seal. Technician B says if a visual inspection does not pinpoint the leak, florescent dye should be put in the oil. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. An oil leak at the rear of the engine may be the rear main seal but if visual inspection is inconclusive, dye should be put in the oil, the engine run, and then check for leaks with a blacklight. Answer D is incorrect. Both Technicians are correct.

Technician A says the plug wires on a failed ignition coil pack must be checked for defects. Technician B says most coil packs are considered waste spark systems. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. An open plug wire may cause the coil pack to internally arc to the primary winding, causing failure of the coil and possibly the module. Most coil packs are waste spark systems in that they fire two spark plugs at one time, one for ignition and one for waste spark on the exhaust stroke. Answer D is incorect. Both Technicians are correct.

Technician A says stuck or sticky valves may cause bent valves. Technician B says a timing belt off by three teeth may cause bent valves. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Any time a valve fails to close at the proper time, the piston may contact it. A sticky or stuck valve is slow to close. If the camshaft and crankshaft are out of synchronization, the piston may contact a valve. Answer D is incorrect. Both Technicians are correct.

Technician A says it is important to relieve pressure on an injector rail before replacing an injector. Technician B says fuel pressure may be 50 psi or higher, depending on the injection system. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Anytime a fuel injection system is opened, it is important to relieve fuel pressure to prevent fuel spray and possible injury. The fuel system may have pressure greater that 50 psi, depending on the type of system. Answer D is incorrect. Both Technicians are correct.

Technician A says that valve keepers must be inspected for wear, cracks, and rounded corners. Technician B says that valve keeper lock grooves must also be checked for wear. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Both the valve keepers and the valve keeper lock grooves in the valve stem must be checked for damage. If the keepers and grooves are not checked, the valve may be released while the engine is running causing damage to the cylinder and head. Answer D is incorrect. Both Technicians are correct.

Technician A says a hydraulic lifter in a pushrod engine may pump up during very high RPM operation. Technician B says this may cause bent valves. Who is correct? A. A Only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. During high RPM operation in a pushrod engine, the lifter may pump up and hold the valve open due to slight amounts of lash in the valve train. When this happens, the valve may be held open and hit by the pistc at the very least, the engine will stall. Answer D is incorrect. Both Technicians are correct.

Technician A says before disassembly of the engine block begins, all main bearing caps must be marked for their location and orientation, if the manufacturer has not already done so. Technician B says cracked design connecting rod caps should be marked with the original orientation and cylinder. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Main bearing caps are not interchangeable and cannot be reversed when reinstalled or binding of the crankshaft may occur. A cracked connecting rod cap will only fit the rod it came with. Answer D is incorrect. Both Technicians are correct.

Technician A says that when removing a cylinder head from an OHC engine, the camshaft may have to be removed first. Technician B says the cylinder head should be cold before removal. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Many OHC engines require removal of the camshaft to access the head bolts. The cylinder head should be cold before removal, particularly with an aluminum head, to prevent inducing warpage when the head bolts are removed. Answer D is incorrect. Both Technicians are correct.

Technician A says most newly designed engines use low tension piston rings. Technician B says that low tension piston rings decrease friction in the cylinder and help improve fuel economy. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Most newly designed engines use low tension piston rings to reduce friction and improve fuel economy. Answer D is incorrect. Both Technicians are correct.

A vehicle is brought in with excessive oil loss. Technician A says the loss may be through the rear main seal. Technician B says bad valve stem seals can cause excessive oil consumption. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Oil can leak past a worn rear main seal. Bad valve stem seals will cause oil to be drawn into the combustion chamber and burned. Answer D is incorrect. Both Technicians are correct.

During teardown, it is noted that several valve stem tips were severely mushroomed. Technician A says the mushroomed tips must be dressed with a file before valve removal. Technician B says this was probably caused by the valve clearance being excessive. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. The normal cause for valve tip mushrooming is excessive clearance, which allows the rocker arm to hammer the valve tip rather than being in constant contact. If the tips are mushroomed, they cannot be removed without filing the tip. If they are driven out with a punch and hammer, the guides and valves will be damaged. Answer D is incorrect. Both Technicians are correct.

Technician A says the main bearing bores are checked for alignment with a straightedge and a feeler gauge. Technician B says main bearing bores that are out of alignment can be corrected by line boring. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. The proper tools to check main bearing bore alignment are the straightedge and feeler gauge; line boring would straighten out of alignment bores. Answer D is incorrect. Both Technicians are correct.

Technician A says the upper oil galleys in the block may be sealed with pipe plugs. Technician B says the oil galley plugs must be removed to properly clean the galleys. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Many upper oil galleys are sealed with pipe plugs that must be removed during cleaning to make sure the galleys are completely clean. Answer D is incorrect. Both Technicians are correct.

An oil pan is being reinstalled on the engine. Technician A says that the oil pan can using RTV. Technician B says that a new gasket may be installed. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. RTV is a gasket maker, so RTV or a new gasket could be installed. Answer D is incorrect. Both Technicians are correct.

Technician A says that during engine reassembly, all rod bearing clearances should be checked. Technician B says the rod bearing inserts should extend slightly above the rod and cap; this is called bearing crush. Who is correct? A. A only B B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. All rod bearing clearances should be checked to ensure proper bearing-to-journal clearance. Bearing crush ensures that the bearing fits tight in the rod when assembled and will not rock. Answer D is incorrect. Both Technicians are correct.

A cylinder leakage test has been performed and one cylinder failed with a leakage of over 80 percent. Technician A says the leakage could be into the cooling system. Technician B says testing for combustion gases in the radiator would confirm the diagnosis. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. A loss of pressure during a cylinder leakage test could be caused by leakage into the cooling system through a blown head gasket. Testing the radiator for combustion gases while the engine is running would confirm the diagnosis. Answer D is incorrect. Both Technicians are correct.

Technician A says an engine oil cooler may be located in one of the radiator tanks. Technician B says a transmission oil cooler may be located in one of the radiator tanks. Who is correct? A. A only B. B only C. Both A and B D. Neither A or B

Answer A is incorrect. Technician B is also correct. Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. An oil cooler tank and/or a transmission cooler may be mounted inside the radiator side tanks. Answer D is incorrect. Both Technicians are correct.

A serpentine belt has just been replaced; it squeals in the morning and during acceleration Technician A says this could be caused by worn pulley grooves. Technician B says a weak tensioner could cause the problem. Who is correct? A. A only. B. B only. C. Both A and B. D. Neither A nor B.

Answer A is incorrect. Technician B is also correct. bor Answer B is incorrect. Technician A is also correct. Answer C is correct. Both Technicians are correct. Worn pulley grooves could cause the belt to slip under load and if the tensioner is not supplying enough tension during start up, the belt will squeal as the alternator charges at higher outputs. Answer D is incorrect. Both Technicians are correct.

A power balance test is being done to pinpoint low performing cylinders. Technician A says there will be a drop in RPM on the poor performing cylinders. Technician B says the results should be within +/- 10 percent across all cylinders of a properly performing engine. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. The RPM would change very little, or not at all, on a cylinder that is not performing properly. Answer B is correct. Only Technician B is correct. The expected results for all cylinders should be within +/- 10 percent of each other. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

A battery-rated at 600 cold cranking amps (CA) is loud tested at one half of its rated CCA for 15 seconds. The results show 10.1 volts. This indicates the battery: A. Is bad and should be replaced. B. Needs recharging. C. Is good. D. Should be retested for 30 seconds at load.

Answer A is incorrect. The battery passed the load test. Answer B is incorrect. The battery passed the load test and should recover its lost voltage after a short period of time. Answer C is correct. The battery load test specification is one-half the cold cranking amps for 15 seconds, and the battery voltage should not drop below 9.6 volts at 70°F. Answer D is incorrect. No further testing is needed; the battery passed the load test.

The water pump is being replaced on a rear-wheel drive vehicle with a longitudinally placed engine. What is the LEAST LIKELY part that will have to be removed? A. The cooling fan B. The fan belt C. The radiator D. The fan shroud

Answer A is incorrect. The cooling fan would be removed. Answer B is incorrect. The belt turning the fan and the water pump would be removed. Answer C is correct. The radiator would not have to be removed. Answer D is incorrect. The fan shroud may have to be removed when the cooling fan is removed.

The technician test drives the customer's car but cannot duplicate the customer's complaint. His next step should be: A. Ask the service writer to call the customer for more information. B. Return the vehicle to the customer with the comment, "No problem found." C. Do a repair based on the customer's complaint. D. Call the customer to get more information such as when and how often the problem occurs.

Answer A is incorrect. The service writer talked to the customer when he brought the vehicle in and may not know the right questions to ask. Answer B is incorrect. The vehicle was brought in for a problem and the customer expects a repair, although sometimes an intermittent problem cannot be duplicated. Answer C is incorrect. No repairs should be made if the complaint cannot be verified. Answer D is correct. If the technician calls the customer, he can ask the pertinent questions to help identify the problem.

Technician A says when removing an engine with an automatic transmission, the transmission torque converter is removed with the engine. Technician B says all the accessories must be removed from the engine before removal. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. The transmission torque converter must be unbolted and pushed back into the transmission pump to prevent damage to the pump during engine removal. Answer B is incorrect. It is usually possible to leave the alternator mounted on the engine during removal. It is best to take as little as possible from the engine before removal. After removing the engine, it is much easier to remove the parts. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. If an engine is removed with the torque converter still attached, the converter nose may bind in the transmission pump and break the pump housing. Due to tight engine compartments, any accessories, wiring, or other components that can be left on the engine during removal will be easier to remove with the engine out of the engine compartment and mounted on an engine stand. The components can be reinstalled before installation.

Technician A says typical piston-to-bore clearance is 0.020 to 0.030 inch. Technician B says typical piston-to-bore clearance is 0.001 to 0.002 inch. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Typical piston-to-bore clearance is 0.001 to 0.002 inch. Answer B is correct. Only Technician B is correct. Typical piston-to-bore clearance is 0.001 to 0.002 inch; this is calculated by measuring the bore and the piston and subtracting. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

During a vacuum check of a poorly running engine, it is found that vacuum holds steady between 8 and 14 in. Hg. Technician A says this may be caused by weak valve springs. Technician B says ignition timing that is off could cause this problem. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Weak valve springs would result in erratic needle movement. Answer B is correct. Only Technician B is correct. Ignition timing that is off may cause low, steady vacuum readings due to improper spark timing. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

Technician A says that when adjusting valves on an engine with mechanical adjustment, the piston must be at BDC on the exhaust stroke. Technician B says some mechanical valve adjustment is done by changing removable lash pads on a bucket. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. When mechanically adjusting valves, it must be done with the piston at TDC compression stroke to ensure all valves for that cylinder are closed. Answer B is correct. Only Technician B is correct. Some engines' camshafts may act on a lash pad and bucket assembly, which directly contacts the valve tip. Answer C is incorrect. Only Technician B is correct. Answer D is incorrect. Technician B is correct.

The customer is concerned about his oil pressure gauge dropping after the vehicle is driven for about 20 miles, although when he starts up, it is normal. When the dipstick is checked after shutdown, it shows below the add mark. When the dipstick is checked after sitting, the oil level shows full. Which of the following is the most likely cause? A. Worn camshaft bearings B. Leaking rear main seal C. Blocked oil return holes in the head D. Weak oil pump

Answer A is incorrect. Worn camshaft bearings may affect oil pressure, but not oil level. Answer B is incorrect. If the rear main seal was leaking, the oil level would stay low from oil loss. Answer C is correct. Blocked return holes in the head will hold the oil in the valve cover and slowly allow it to drain back into the pan. Answer D is incorrect. A weak oil pump will cause low oil pressure, not oil use.

All of the following are causes of low engine oil pressure EXCEPT: A. Worn crankshaft main bearings. B. Weak oil pump pressure relief valve spring. C. Stuck open pressure relief valve. D. Restricted pushrod oil passages.

Answer A is incorrect. Worn crankshaft main bearings will cause low oil pressure. Answer B is incorrect. A weak oil pump pressure relief valve spring will not allow oil pressure to build to the proper pressure before allowing the oil to return to the oil pan from the oil pump. Answer C is incorrect. A stuck open pressure relief valve will cause low oil pressure. Answer D is correct. Restricted pushrod oil passages will affect oil delivery to the rocker arms, but will not affect oil pressure.

A customer brings his car to you complaining of a loss of oil pressure after extended driving. Which of the following is the most likely cause? A. Worn main bearings B. Weak oil pump C. Defective oil sending unit D. Trash in the oil pan stopping-up the oil pickup screen

Answer A is incorrect. Worn main bearings will cause low oil pressure all the time. Answer B is incorrect. A weak oil pump will cause low oil pressure all the time. Answer C is incorrect. A defective oil sending unit will show low pressure all the time. Answer D is correct. If the complaint is loss of oil pressure after extended driving, suspect trash in the oil pan being picked up by the oil pickup screen; this will block oil flow to the pump.

The customer questions the large amount of blue smoke coming out of his tailpipe continuously. Technician A says the problem may be worn main bearings. Technician B says this may be caused by excess fuel in the combustion chamber. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

Answer A is incorrect. Worn main bearings will make noise but will not allow oil to enter the combustion chamber. Answer B is incorrect. Excessive fuel in the combustion chamber will produce black smoke from the tailpipe. Answer C is incorrect. Neither Technician is correct. Answer D is correct. Neither Technician is correct. Although worn main bearing may cause noise or engine failure, they will not cause oil to enter the combustion chamber; the rings will prevent that from occurring. Blue smoke is an indication of oil being burned in the combustion chamber. Excess unburned fuel in the combustion chamber is indicated by black smoke from the tailpipe.

The LEAST LIKELY cause of excessive blue smoke from the exhaust of a turbocharged engine is: A. Worn piston rings. B. Bad valve stem seals. C. A PCV valve stuck in the open position. D. Worn turbocharger seals.

Answer A is incorrect. Worn piston rings will allow oil to enter the combustion chamber causing blue smoke in the exhaust. Answer B is incorrect. Bad valve stem seals will allow oil in the combustion chamber. Answer C is correct. A stuck open PCV valve will not cause oil in the combustion chamber. Answer D is incorrect. Worn turbocharger seals on the intake side will allow oil to be drawn into the combustion chamber.