ASE Automobile (A1–A8) — All Questions

A cylinder head is warped beyond specification. Which service is normally required to restore a flat sealing surface?

• a.Retorquing the head while hot
• b.Replacing the head bolts only
• c.Resurfacing (machining) the head✓
• d.Installing a thicker head gasket

A warped head must be resurfaced by machining to bring the deck within flatness specification. A thicker gasket will not correct an uneven surface, and simply retorquing does not remove the warp. Excessive material removal, however, can raise compression and change valve timing on some engines.

Technician A says a blown head gasket can allow coolant to enter a cylinder and cause white exhaust smoke. Technician B says it can cause bubbles in the coolant recovery tank from combustion gases. Who is correct?

• a.Technician A only
• b.Technician B only
• c.Both A and B✓
• d.Neither A nor B

A failed head gasket can leak both ways: coolant into the cylinder produces white steam-like exhaust, and combustion pressure into the cooling system produces bubbles and possible overheating. Both technicians describe valid symptoms. A cooling-system pressure test and a combustion-gas (block) test help confirm the diagnosis.

A valve that fails to seat fully will most directly cause which condition?

• a.High oil pressure
• b.Low cylinder compression on that cylinder✓
• c.Excessive oil consumption only
• d.A stuck lifter

A valve that does not seat allows combustion pressure to escape, lowering compression in that cylinder and often causing a misfire. A cylinder leak-down test with air hissing from the intake or exhaust confirms an intake or exhaust valve leak. Burned valves and carbon deposits are common causes.

On an overhead-cam engine, excessive valve lash (clearance) most commonly produces which symptom?

• a.Low oil pressure
• b.A clicking or tapping noise from the valvetrain✓
• c.Blue exhaust smoke
• d.Loss of coolant

Too much clearance in the valvetrain lets components hammer against one another, producing a rhythmic tapping that changes with engine speed. Insufficient lash, by contrast, can hold valves open and burn them. Proper adjustment restores quiet operation and correct valve timing.

Technician A says the PCV system routes crankcase blow-by vapors into the intake to be burned. Technician B says a stuck PCV valve can cause rough idle or oil leaks. Who is correct?

• a.Technician B only
• b.Both A and B✓
• c.Technician A only
• d.Neither A nor B

The PCV system draws blow-by gases into the intake so they are burned rather than vented, and a stuck valve can cause rough idle, oil leaks, or high oil consumption. Both technicians are correct. This reduces sludge formation and emissions.

A mechanic measures cylinder taper by comparing bore diameter at the top of ring travel to the bottom. This measurement is taken with a:

• a.Feeler gauge
• b.Compression tester
• c.Dial bore gauge or inside micrometer✓
• d.Vacuum gauge

Cylinder taper and out-of-round are measured with a dial bore gauge or inside micrometer at several points in the bore. Wear is greatest at the top of ring travel where combustion heat and pressure are highest. Excessive taper requires boring and oversize pistons.

Technician A says low oil pressure only at idle on a high-mileage engine can be caused by worn bearing clearances. Technician B says a worn oil pump or diluted oil can also lower pressure. Who is correct?

• a.Both A and B✓
• b.Technician A only
• c.Technician B only
• d.Neither A nor B

Worn bearing clearances let oil escape faster than the pump maintains pressure at low speed, and a worn pump or fuel-diluted oil reduces pressure as well. Both technicians are correct. Verify with a mechanical gauge before condemning parts.

Which cooling-system component regulates coolant flow based on engine temperature?

• a.Heater core
• b.Radiator cap
• c.Thermostat✓
• d.Water pump

The thermostat stays closed until the engine reaches operating temperature, then opens to allow coolant to circulate through the radiator. A stuck-closed thermostat causes overheating; a stuck-open one causes slow warm-up and poor heater output. It is a common, inexpensive cause of temperature complaints.

A radiator pressure cap raises the system's boiling point primarily because:

• a.It adds antifreeze to the coolant
• b.It lowers the coolant level
• c.It speeds up the water pump
• d.Increased pressure raises the coolant's boiling temperature✓

Sealing the system under pressure raises the boiling point of the coolant, allowing higher operating temperatures without boil-over. A weak or faulty cap lowers the effective boiling point and can cause coolant loss. Caps should be pressure-tested when overheating is suspected.

Blue smoke from the exhaust under acceleration most often indicates:

• a.A lean misfire
• b.A rich fuel mixture
• c.Coolant in the combustion chamber
• d.Oil entering the combustion chamber✓

Blue smoke indicates oil is being burned, commonly from worn rings, cylinder walls, or valve guide seals. White smoke suggests coolant, and black smoke suggests excess fuel. A leak-down or compression test helps localize the source.

Technician A says timing-chain stretch can retard valve timing and set a camshaft/crankshaft correlation code. Technician B says a stretched timing chain has no effect on engine performance. Who is correct?

• a.Both A and B
• b.Technician B only
• c.Neither A nor B
• d.Technician A only✓

A stretched or worn timing chain changes the relationship between crankshaft and camshaft position, retarding valve timing and often setting a correlation DTC. This can cause rough running and reduced power. Technician B is incorrect because timing is directly affected.

Head bolts that use a torque-to-yield (TTY) design should be:

• a.Coated with anti-seize before reuse
• b.Replaced with new bolts during reassembly✓
• c.Reused indefinitely
• d.Torqued to half the final value only

Torque-to-yield bolts are stretched into their plastic range for a uniform clamp load and should not be reused. Reusing them risks uneven clamping and gasket failure. Always follow the specified torque-plus-angle sequence with new bolts.

The main function of engine oil, besides lubrication, includes all of the following EXCEPT:

• a.Generating spark for combustion✓
• b.Cleaning and suspending contaminants
• c.Sealing between rings and cylinder walls
• d.Cooling internal components

Engine oil lubricates, cools, cleans, and helps seal the rings, but it plays no role in generating spark. Spark is produced by the ignition system. Detergent and dispersant additives keep contaminants suspended until the filter or an oil change removes them.

A rhythmic knocking noise that is loudest under load and disappears when one cylinder is disabled most likely indicates:

• a.A loose accessory belt
• b.A worn connecting-rod bearing on that cylinder✓
• c.A sticking valve
• d.An exhaust leak

A rod bearing knock is load-sensitive and typically quiets when that cylinder's contribution is removed by disabling its injector or spark. Loose belts and exhaust leaks make different noises unrelated to individual cylinders. Excessive rod bearing clearance is confirmed with Plastigage during disassembly.

Coolant is leaking internally and the engine oil appears milky. The MOST likely cause is:

• a.A worn timing belt
• b.A failed head gasket or cracked block/head✓
• c.A clogged air filter
• d.A stuck thermostat

A milky, tan appearance in the oil indicates coolant contamination, commonly from a head gasket failure or a crack that connects a coolant passage to the oil. Continued operation damages bearings. Pressure and combustion-gas testing help pinpoint the leak path.

Before final assembly, plastigage is used to measure:

• a.Piston ring end gap
• b.Valve spring free length
• c.Bearing oil clearance✓
• d.Cylinder bore taper

Plastigage is a crushable plastic thread that indicates bearing oil clearance when compared to a scale after the cap is torqued. Ring end gap is measured with a feeler gauge in the bore, and bore taper with a bore gauge. Correct clearance is essential for oil film and bearing life.

In an automatic transmission, the torque converter's function is to:

• a.Engage the parking pawl
• b.Couple the engine to the transmission and multiply torque✓
• c.Generate line pressure directly
• d.Cool the engine oil

The torque converter is a fluid coupling that transmits power from the engine to the transmission and multiplies torque during acceleration. Its lockup clutch mechanically links the engine and transmission at cruise to improve fuel economy. The pump, not the converter, generates line pressure.

Technician A says burnt-smelling, dark automatic transmission fluid can indicate overheating and clutch damage. Technician B says fluid color and smell never matter. Who is correct?

• a.Technician B only
• b.Both A and B
• c.Neither A nor B
• d.Technician A only✓

Dark, burnt-smelling ATF indicates overheating and worn friction material from slipping clutches or bands. Healthy fluid is typically red and translucent. Technician B is wrong because fluid condition is an important diagnostic clue.

A manual transmission clutch that slips under load, especially in higher gears, most commonly indicates:

• a.Too much clutch pedal free play
• b.A broken motor mount
• c.A dry pilot bearing
• d.A worn clutch disc or weak pressure plate✓

A worn friction disc or weak pressure plate cannot hold torque, so the clutch slips under load and engine rpm rises without matching acceleration. Slipping generates heat that accelerates wear. Insufficient free play, not too much, can also cause slipping.

Constant-velocity (CV) joints are used on front-wheel-drive axles primarily because they:

• a.Transmit power smoothly through varying steering angles✓
• b.Are cheaper than U-joints
• c.Require no lubrication
• d.Eliminate the need for a differential

CV joints deliver constant rotational speed while the axle operates through the wide angles created by steering and suspension travel. A torn CV boot lets grease escape and dirt enter, leading to a clicking noise during turns. Boot inspection is a routine maintenance check.

A clicking noise from the front of a FWD vehicle that increases when turning sharply is most likely caused by:

• a.A worn outer CV joint✓
• b.An unbalanced tire
• c.A leaking transmission seal
• d.A worn wheel bearing

A worn outer CV joint clicks under the load of a sharp turn, and the noise usually worsens with steering angle. A torn boot that allowed grease loss is a frequent cause. Wheel bearing noise, by contrast, is typically a steady drone that changes with vehicle speed.

The differential in a rear axle allows:

• a.The transmission to shift gears
• b.The drive wheels to rotate at different speeds during turns✓
• c.The driveshaft to change length
• d.The engine to idle smoothly

The differential splits torque to the drive wheels while allowing them to turn at different speeds when cornering, since the outer wheel travels farther. A limited-slip design adds resistance to reduce wheel spin. Whining or howling noises often indicate worn or improperly set-up gears.

Technician A says a worn driveshaft U-joint can cause a clunk on acceleration. Technician B says it can cause a vibration that increases with vehicle speed. Who is correct?

• a.Neither A nor B
• b.Technician A only
• c.Both A and B✓
• d.Technician B only

A worn universal joint clunks when torque is applied and vibrates more as speed rises because the joint develops play. Both technicians describe valid symptoms. Rust-colored dust around the caps is an early sign of failure.

A vehicle has a final drive ratio of 3.73:1. This means the:

• a.Driveshaft turns 3.73 times for each wheel revolution✓
• b.Engine turns at 3.73 percent of wheel speed
• c.Transmission has 3.73 forward gears
• d.Wheels turn 3.73 times per driveshaft revolution

A 3.73:1 final drive means the driveshaft (ring-and-pinion input) turns 3.73 times for every one revolution of the axle/wheel. A numerically higher ratio improves acceleration but raises cruising rpm. Ratio is found by dividing ring-gear teeth by pinion-gear teeth.

Technician A says most dipstick-equipped automatics are checked with the engine running at operating temperature. Technician B says fluid level is unaffected by temperature. Who is correct?

• a.Technician B only
• b.Neither A nor B
• c.Technician A only✓
• d.Both A and B

Dipstick-equipped automatics are checked hot with the engine running and the selector cycled, and fluid expands with temperature so the reading depends on it. Technician B is wrong. Many modern units use a sealed fill within a specified fluid-temperature window.

Technician A says a slipping band or clutch pack can cause delayed or harsh shifts. Technician B says low line pressure can cause slipping and overheating. Who is correct?

• a.Both A and B✓
• b.Technician A only
• c.Technician B only
• d.Neither A nor B

Worn friction elements slip and cause delayed, harsh, or flaring shifts, while low line pressure reduces clamping force and leads to slippage and heat. Both conditions are valid causes of shift complaints. A pressure test and scan-tool data help isolate the fault.

Excessive clutch pedal free play in a manual transmission can cause:

• a.Loss of transmission fluid
• b.The flywheel to warp
• c.Incomplete clutch release, making shifting difficult✓
• d.The clutch to slip under load

Too much free play prevents the clutch from fully disengaging, causing grinding or hard shifting because the disc still contacts the flywheel. Too little free play causes slipping. Hydraulic systems self-adjust, while cable systems may require manual adjustment.

A gear ratio is calculated by dividing the number of teeth on the driven gear by the number on the drive gear. A drive gear with 12 teeth turning a driven gear with 36 teeth produces a ratio of:

• a.2:1
• b.3:1✓
• c.4:1
• d.1:3

Dividing 36 driven teeth by 12 drive teeth gives a 3:1 reduction, meaning the drive gear turns three times for each output revolution. This multiplies torque while reducing speed. Understanding ratios is essential for diagnosing driveline gearing and speedometer calibration.

A whining noise from an automatic transmission that changes with engine speed but is present in Park and Neutral most likely points to:

• a.A slipping clutch pack
• b.A worn output shaft bearing
• c.A worn CV joint
• d.A failing transmission fluid pump✓

Because the pump is driven by the converter hub whenever the engine runs, a pump-related whine is present in Park and Neutral and varies with engine rpm. Output-related noises appear only when the vehicle moves. Low fluid or aeration can produce similar sounds.

The pilot bearing or bushing in a manual-transmission vehicle supports the:

• a.Throwout bearing
• b.Tip of the transmission input shaft✓
• c.Flywheel ring gear
• d.Clutch release fork

The pilot bearing supports the front tip of the input shaft in the end of the crankshaft, keeping it centered. A worn pilot bearing causes noise and hard shifting, especially with the clutch depressed. It should be inspected or replaced whenever the clutch is serviced.

Camber angle is defined as the:

• a.Inward or outward tilt of the wheel from vertical, viewed from the front✓
• b.Difference in toe between left and right wheels
• c.Forward or rearward tilt of the steering axis
• d.Angle of the tie rod to the ground

Camber is the inward (negative) or outward (positive) tilt of the wheel from true vertical when viewed from the front. Incorrect camber causes uneven tire wear on one shoulder and can pull the vehicle to one side. It is adjusted where the suspension design allows.

Excessive positive caster generally results in:

• a.Wander at highway speed
• b.Rapid center-tread wear
• c.Loss of directional stability
• d.Increased steering effort but improved straight-line stability✓

Positive caster tilts the steering axis rearward at the top, improving straight-line stability and steering return but increasing effort. Too little caster causes wander and poor return. Caster is measured during alignment and typically compared side to side.

Toe refers to the:

• a.Height of the vehicle at the fender
• b.Vertical tilt of the wheel
• c.Rearward tilt of the steering axis
• d.Difference in distance between the front and rear of a pair of tires, viewed from above✓

Toe is the difference between the leading and trailing edges of the tires viewed from above; toe-in means the fronts are closer together. Incorrect toe is the leading cause of rapid, feathered tire wear. It is the most critical alignment angle for tire life and is always adjustable.

A tire worn on both inner and outer edges, with good tread in the center, most likely indicates:

• a.Over-inflation
• b.Excessive positive camber
• c.Chronic under-inflation✓
• d.A worn tie rod end

Under-inflation lets the tire ride on both shoulders while the center bears less load, wearing both edges. Over-inflation does the opposite, wearing the center. Correct inflation and periodic pressure checks prevent this pattern.

Technician A says a worn tie rod end can cause a toe change and tire wear. Technician B says it can cause excessive play in the steering and a failed alignment. Who is correct?

• a.Both A and B✓
• b.Technician B only
• c.Neither A nor B
• d.Technician A only

A worn tie rod end introduces play that changes toe as the wheel moves, causing wandering and feathered tire wear, and it will prevent a stable alignment. Both technicians are correct. Worn steering and suspension parts must be replaced before performing an alignment.

Technician A says worn shocks or struts can cause the body to keep bouncing after a bump. Technician B says worn dampers have no effect on tire wear. Who is correct?

• a.Both A and B
• b.Technician A only✓
• c.Neither A nor B
• d.Technician B only

Worn shocks lose their ability to dampen spring oscillation, so the body keeps bouncing after a bump, and weak dampers also cause tire cupping. Technician B is wrong because damper wear does affect tire wear. A bounce test and leak inspection confirm the condition.

Cupping or scalloping tire wear is most commonly associated with:

• a.Worn suspension dampers or unbalanced wheels✓
• b.Excessive toe-in
• c.A slipping clutch
• d.Over-torqued lug nuts

Cupping, a series of dips around the tread, results from the tire bouncing due to worn shocks/struts or from imbalance. It usually comes with a noise that changes with speed. Correcting the damper or balance issue and rotating tires helps.

The purpose of a stabilizer (sway) bar is to:

• a.Support the full weight of the vehicle
• b.Adjust ride height
• c.Absorb road shock like a shock absorber
• d.Reduce body roll during cornering✓

The stabilizer bar links the left and right suspension to resist body lean when cornering, improving handling. Worn sway bar links or bushings produce a rattle or clunk over bumps. It does not carry ride height or primary spring load.

Technician A says a side-to-side camber difference can cause a vehicle to pull toward the more positive side. Technician B says a defective tire can also cause a pull. Who is correct?

• a.Neither A nor B
• b.Technician B only
• c.Both A and B✓
• d.Technician A only

A cross-camber difference pulls the vehicle toward the more positive side, and a defective (conicity) tire can pull as well. Both technicians are correct. Compare cross-camber and cross-caster and swap tires side to side to isolate a tire pull.

In a power rack-and-pinion steering system, increased steering effort in only one direction most likely indicates:

• a.A bent stabilizer bar
• b.An internal leak or valve fault in the steering gear✓
• c.A low battery
• d.A worn wheel bearing

Effort that is heavy in one direction points to an internal fault such as worn seals or a control valve problem that fails to direct assist correctly. Uniformly hard steering suggests low fluid or a pump/belt issue. Electric power steering faults set codes and can be scanned.

The included angle in an alignment is the sum of:

• a.Toe and camber
• b.Caster and toe
• c.Camber and steering axis inclination (SAI)✓
• d.Caster and SAI

Included angle equals camber plus SAI and is useful for detecting bent spindles or struts, since SAI is built in and not adjustable. If included angle differs side to side, a component is likely bent. It is a diagnostic angle rather than an adjustable one.

A steering wheel that is off-center after an alignment, though the vehicle tracks straight, usually indicates:

• a.Improperly set toe split between the two front wheels✓
• b.A weak spring
• c.Excessive camber
• d.A worn wheel bearing

When total toe is correct but not divided equally between the wheels, the steering wheel sits off-center even though the vehicle goes straight. Centering the steering and re-setting individual toe corrects it. This is checked with the steering wheel locked in the centered position.

Technician A says tires should be rotated to promote even wear. Technician B says the tire's load index and speed rating should meet or exceed the vehicle's requirements. Who is correct?

• a.Neither A nor B
• b.Technician B only
• c.Both A and B✓
• d.Technician A only

Rotation evens out the different wear rates at each position, and replacement tires must meet the vehicle's load and speed ratings for safe operation. Both statements are correct service practice. Always follow the recommended rotation pattern for the drivetrain type.

Technician A says a worn ball joint can cause clunking, wander, and uneven tire wear. Technician B says a load-carrying ball joint should be checked with its load removed per the procedure. Who is correct?

• a.Both A and B✓
• b.Technician A only
• c.Neither A nor B
• d.Technician B only

A worn ball joint clunks, wanders, and wears tires unevenly, and load-carrying joints are checked unloaded so the measured axial and radial play is accurate. Both technicians are correct. A worn ball joint can fail catastrophically if ignored.

The main purpose of a wheel alignment is to:

• a.Adjust the brakes
• b.Set suspension angles for proper handling and even tire wear✓
• c.Increase engine power
• d.Balance the wheels

Alignment sets camber, caster, and toe so the tires meet the road correctly, giving good handling, steering return, and even tire wear. Balancing is a separate operation addressing weight distribution. Worn parts must be repaired before alignment angles will hold.

Wheel/tire imbalance is most often felt as:

• a.A vibration that appears at a particular speed✓
• b.Hard steering at low speed
• c.A pull to one side
• d.A grinding noise when braking

An out-of-balance wheel creates a vibration that emerges at a specific speed as the heavy spot spins. Static and dynamic balancing corrects it by adding weights. A pull, by contrast, is usually an alignment or tire construction issue.

A brake pedal that slowly sinks to the floor while held under steady pressure most likely indicates:

• a.Glazed brake pads
• b.A failing master cylinder (internal leak)✓
• c.Warped rotors
• d.Air in the lines only

A pedal that gradually falls under steady pressure indicates fluid bypassing internally in the master cylinder past worn seals. An external leak would lose fluid visibly. Replacing the master cylinder and bleeding the system restores a firm pedal.

Technician A says a spongy brake pedal is commonly caused by air in the hydraulic system. Technician B says air in the lines increases braking power. Who is correct?

• a.Neither A nor B
• b.Both A and B
• c.Technician B only
• d.Technician A only✓

Air is compressible, so it makes the pedal feel soft or spongy and reduces braking effectiveness; proper bleeding removes it. Technician B is wrong because air degrades rather than improves braking. Bleeding in the correct sequence restores a firm pedal.

Technician A says a pulsating brake pedal is usually caused by air in the hydraulic lines. Technician B says it is usually caused by rotor thickness variation or excessive lateral runout. Who is correct?

• a.Neither A nor B
• b.Technician A only
• c.Both A and B
• d.Technician B only✓

Thickness variation or warp causes the pads to move in and out as the disc turns, producing a pulsation felt in the pedal, while air produces a soft pedal instead. Technician B is correct. Measuring runout and thickness variation confirms it.

The primary purpose of a brake power booster is to:

• a.Store brake fluid
• b.Adjust the parking brake
• c.Prevent wheel lockup
• d.Reduce the pedal effort required to apply the brakes✓

The vacuum or hydraulic booster multiplies the driver's pedal force so less effort is needed for firm braking. A failed vacuum booster or leaking check valve produces a hard pedal. It works with, not instead of, the hydraulic system.