247SimpleTests
ASVAB · Vehicle Systems

What is the purpose of engine oil?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

To lubricate moving engine parts, reduce friction, and help cool and clean the engine

  1. A To inflate the tires
  2. B To lubricate moving engine parts, reduce friction, and help cool and clean the engine
  3. C To power the spark plugs
  4. D To cool the radiator

Why this is the answer

ENGINE OIL LUBRICATES moving engine parts, REDUCING FRICTION and wear; it also helps COOL and CLEAN the engine (carrying away heat and contaminants). ASVAB Auto Information tests the lubrication system. Without oil, metal parts would grind together, overheat, and seize. Oil must be changed periodically because it degrades and collects contaminants. The OIL FILTER removes particles. Knowing oil's primary job (lubrication/reducing friction, plus cooling and cleaning) is commonly tested auto knowledge.
Source: ASVAB Auto Information — Lubrication System

Practice more questions

This question is from our ASVAB Practice Tests practice test. Take the full practice test to test your knowledge across all Vehicle Systems and other topics.

Take the Auto Information practice test →

About this topic: Vehicle Systems

Vehicle systems questions ask how the major subsystems work together — fuel, ignition, cooling, lubrication, electrical, exhaust and drivetrain — and what symptom points to which system. You do not need mechanic-level depth, just the function of each part and the common failure signs. This is one of 9 Auto Information questions on vehicle systems, each with a full explanation on a single study page.

New to this exam? Our ASVAB exam guide explains the format, scoring, and how to prepare.

Related questions

Vehicle Systems

What is the main function of the alternator in a vehicle?

 Vehicle Systems

What does the cooling system (radiator and coolant) do in a vehicle?

 Vehicle Systems

What component ignites the air-fuel mixture in a gasoline engine?

 Vehicle Systems

What is the function of the brake system's master cylinder?

Recommended study materials

Study guide

ASVAB Total Prep (Kaplan)

Kaplan's complete ASVAB guide with 1,000+ practice questions, 6 full-length tests, and AFQT focus.

Check Price → Study guide

Barron's ASVAB with Online Tests 12th Ed.

Comprehensive ASVAB review for all nine subtests with full-length practice exams and online tools.

Check Price → Study guide

ASVAB for Dummies 4th Ed. (Wiley)

Accessible, thorough ASVAB prep covering all subtests with tips for boosting your AFQT score.

Check Price →

As an Amazon Associate, CJ Affiliate, and AWIN publisher we earn from qualifying purchases. Links above are affiliate links. Full disclosure →