NYC Auto Mechanic Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary function of engine oil is to
A. Cool the engine only
B. Seal the combustion chamber
C. Lubricate moving engine parts
D. Increase fuel octane
Correct Answer: C. Lubricate moving engine parts
Rationale: Engine oil reduces friction and wear between moving
components, helping prevent overheating and damage.
2. A misfiring engine is most likely caused by
A. Low tire pressure
B. Faulty spark plug
, C. Clogged radiator
D. Worn brake pads
Correct Answer: B. Faulty spark plug
Rationale: Spark plugs ignite the air-fuel mixture; when faulty, combustion
is inconsistent, causing misfires.
3. What component stores electrical energy for vehicle starting?
A. Alternator
B. Starter motor
C. Battery
D. Ignition coil
Correct Answer: C. Battery
Rationale: The battery supplies stored electrical power needed to start the
engine.
4. Excessive black exhaust smoke usually indicates
A. Oil burning
B. Coolant leak
C. Rich air-fuel mixture
D. Lean air-fuel mixture
,Correct Answer: C. Rich air-fuel mixture
Rationale: Too much fuel relative to air causes incomplete combustion,
producing black smoke.
5. The alternator’s main function is to
A. Start the engine
B. Store electrical energy
C. Charge the battery and power electrical systems
D. Control ignition timing
Correct Answer: C. Charge the battery and power electrical systems
Rationale: The alternator generates electricity while the engine runs.
6. Brake fade is most commonly caused by
A. Cold brakes
B. Worn tires
C. Overheating of brake components
D. Low transmission fluid
Correct Answer: C. Overheating of brake components
Rationale: Excessive heat reduces braking efficiency by lowering friction.
7. The purpose of a catalytic converter is to
A. Increase engine power
, B. Reduce engine noise
C. Reduce harmful exhaust emissions
D. Improve fuel economy
Correct Answer: C. Reduce harmful exhaust emissions
Rationale: Catalytic converters convert toxic gases into less harmful
substances.
8. What tool is used to measure cylinder compression?
A. Vacuum gauge
B. Torque wrench
C. Compression tester
D. Multimeter
Correct Answer: C. Compression tester
Rationale: A compression tester measures pressure inside engine cylinders.
9. A vehicle pulling to one side during braking usually indicates
A. Bad alternator
B. Uneven brake application
C. Low coolant
D. Faulty fuel pump
Correct Answer: B. Uneven brake application
Rationale: One brake may be grabbing more than the other.
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary function of engine oil is to
A. Cool the engine only
B. Seal the combustion chamber
C. Lubricate moving engine parts
D. Increase fuel octane
Correct Answer: C. Lubricate moving engine parts
Rationale: Engine oil reduces friction and wear between moving
components, helping prevent overheating and damage.
2. A misfiring engine is most likely caused by
A. Low tire pressure
B. Faulty spark plug
, C. Clogged radiator
D. Worn brake pads
Correct Answer: B. Faulty spark plug
Rationale: Spark plugs ignite the air-fuel mixture; when faulty, combustion
is inconsistent, causing misfires.
3. What component stores electrical energy for vehicle starting?
A. Alternator
B. Starter motor
C. Battery
D. Ignition coil
Correct Answer: C. Battery
Rationale: The battery supplies stored electrical power needed to start the
engine.
4. Excessive black exhaust smoke usually indicates
A. Oil burning
B. Coolant leak
C. Rich air-fuel mixture
D. Lean air-fuel mixture
,Correct Answer: C. Rich air-fuel mixture
Rationale: Too much fuel relative to air causes incomplete combustion,
producing black smoke.
5. The alternator’s main function is to
A. Start the engine
B. Store electrical energy
C. Charge the battery and power electrical systems
D. Control ignition timing
Correct Answer: C. Charge the battery and power electrical systems
Rationale: The alternator generates electricity while the engine runs.
6. Brake fade is most commonly caused by
A. Cold brakes
B. Worn tires
C. Overheating of brake components
D. Low transmission fluid
Correct Answer: C. Overheating of brake components
Rationale: Excessive heat reduces braking efficiency by lowering friction.
7. The purpose of a catalytic converter is to
A. Increase engine power
, B. Reduce engine noise
C. Reduce harmful exhaust emissions
D. Improve fuel economy
Correct Answer: C. Reduce harmful exhaust emissions
Rationale: Catalytic converters convert toxic gases into less harmful
substances.
8. What tool is used to measure cylinder compression?
A. Vacuum gauge
B. Torque wrench
C. Compression tester
D. Multimeter
Correct Answer: C. Compression tester
Rationale: A compression tester measures pressure inside engine cylinders.
9. A vehicle pulling to one side during braking usually indicates
A. Bad alternator
B. Uneven brake application
C. Low coolant
D. Faulty fuel pump
Correct Answer: B. Uneven brake application
Rationale: One brake may be grabbing more than the other.
