AFCT Auto and Shop Information 2 — Questions and Answers
Question 1: What is the primary function of a vehicle's alternator?
- To start the engine
- To charge the battery and power electrical systems (Correct answer)
- To cool the engine
- To filter exhaust gases
Correct answer: To charge the battery and power electrical systems
The alternator generates electricity to charge the battery and power electrical systems while the engine runs.
The alternator is belt-driven by the engine and converts mechanical energy into AC electrical energy, then rectified to DC. It charges the battery and powers all electrical systems while the engine runs. A failing alternator causes dimming lights or a dead battery.
Question 2: What type of saw has fine teeth and is specifically designed for cutting metal?
- Circular saw
- Hacksaw (Correct answer)
- Coping saw
- Table saw
Correct answer: Hacksaw
A hacksaw has a fine-toothed blade held in a C-shaped frame, designed for cutting metal and other hard materials.
A hacksaw is a fine-toothed saw for cutting metal. It features a C-shaped frame holding a thin, replaceable blade under tension. Blades typically have 14-32 teeth per inch. When using a hacksaw, cut on the push stroke with steady pressure.
Question 3: What does the cooling system thermostat in an engine do?
- Pumps coolant through the engine
- Regulates engine temperature by controlling coolant flow (Correct answer)
- Filters debris from the coolant
- Pressurizes the cooling system
Correct answer: Regulates engine temperature by controlling coolant flow
The thermostat opens and closes based on engine temperature, controlling coolant flow to maintain optimal operating temperature.
The thermostat is a temperature-sensitive valve between the engine and radiator. When cold, it stays closed for quick warm-up. Once coolant reaches about 180-200 degrees F, it opens to allow radiator cooling. A stuck-closed thermostat causes overheating; stuck-open causes slow warm-up.
Question 4: Which tool is used to measure the inside diameter of a cylinder?
- Outside micrometer
- Telescoping gauge (Correct answer)
- Torque wrench
- Feeler gauge
Correct answer: Telescoping gauge
A telescoping gauge is inserted into a cylinder bore and expanded to contact the walls, then measured with a micrometer.
A telescoping gauge has spring-loaded plungers that expand inside a bore. The tool is inserted, allowed to expand to contact the cylinder walls, then locked. It is removed and measured with an outside micrometer to determine the bore diameter.
Question 5: What is the purpose of motor oil in an engine?
- Only to cool the engine
- To lubricate, cool, clean, and seal engine components (Correct answer)
- Only to prevent rust
- To increase fuel combustion
Correct answer: To lubricate, cool, clean, and seal engine components
Motor oil lubricates moving parts, cools components, cleans deposits, and helps seal piston rings against cylinder walls.
Motor oil performs four critical functions: lubrication (reduces friction), cooling (carries heat away), cleaning (detergent additives suspend debris), and sealing (fills gaps between piston rings and cylinder walls). Regular oil changes are essential because oil degrades over time.
Question 6: What is the purpose of a torque wrench?
- To loosen extremely tight bolts
- To tighten fasteners to a specific tension (Correct answer)
- To strip damaged bolt heads
- To measure bolt diameter
Correct answer: To tighten fasteners to a specific tension
A torque wrench measures and limits the rotational force applied to a fastener, ensuring proper tightening to specification.
A torque wrench applies a specific amount of rotational force measured in foot-pounds or Newton-meters. This is critical for components like cylinder head bolts and wheel lug nuts where under- or over-tightening causes problems. Common types include click-type, beam-type, and digital.
AFCT Auto and Shop Information 2
What is the primary function of a vehicle's alternator?