Car Tuning Car Maintenance 3 — Questions and Answers
Question 1: What does it mean when your car's battery tests at 12.0V with the engine off?
- The battery is fully charged
- The battery is at approximately 50% charge and may need replacement soon (Correct answer)
- The battery is completely dead
- The battery has a bad cell and must be replaced immediately
Correct answer: The battery is at approximately 50% charge and may need replacement soon
A fully charged 12V lead-acid battery reads about 12.6V; 12.0V indicates roughly 50% state of charge.
Question 2: Which maintenance task is most critical before installing a performance supercharger?
- Upgrading the exhaust manifold
- Ensuring the engine's compression rings and seals are in good condition (Correct answer)
- Replacing the fuel cap
- Painting the engine bay
Correct answer: Ensuring the engine's compression rings and seals are in good condition
A supercharger dramatically increases cylinder pressure, so worn rings or leaking seals will fail quickly under boost.
Question 3: What is the function of a coolant overflow reservoir (expansion tank)?
- It stores extra motor oil
- It catches coolant that expands when hot and returns it to the radiator when cool (Correct answer)
- It filters the coolant
- It pressurizes the cooling system manually
Correct answer: It catches coolant that expands when hot and returns it to the radiator when cool
As coolant heats and expands, excess flows into the reservoir; as the engine cools, the pressure drop draws it back into the radiator.
Question 4: Why should you never open a radiator cap immediately after the engine has been running?
- Coolant will evaporate too quickly
- The system is pressurized and scalding coolant can spray out (Correct answer)
- It will void your warranty
- The coolant level cannot be read when hot
Correct answer: The system is pressurized and scalding coolant can spray out
Cooling systems operate above atmospheric pressure; removing the cap while hot releases that pressure explosively, ejecting boiling coolant.
Question 5: What causes a serpentine belt to squeal, especially on startup?
- Overly tight tensioner
- Belt glazing, slipping, or a seized accessory pulley (Correct answer)
- Too much engine oil
- Low tire pressure
Correct answer: Belt glazing, slipping, or a seized accessory pulley
A glazed or slipping serpentine belt loses grip on pulleys, creating a high-pitched squeal that is often loudest during cold starts.
Question 6: When bleeding brakes, what is the correct starting point on most vehicles?
- The closest wheel to the master cylinder
- The farthest wheel from the master cylinder (usually rear passenger) (Correct answer)
- Any wheel in any order
- The front driver's wheel first
Correct answer: The farthest wheel from the master cylinder (usually rear passenger)
Bleeding from the farthest point first ensures air is pushed completely out of the longest brake lines.
Question 7: What does a strong fuel smell from the engine bay indicate?
- Normal evaporation from the fuel tank
- A possible fuel line, injector, or fuel rail leak requiring immediate inspection (Correct answer)
- The engine is running rich due to a cold start
- The catalytic converter is overheating
Correct answer: A possible fuel line, injector, or fuel rail leak requiring immediate inspection
A persistent fuel odor under the hood signals a leak in the high-pressure fuel circuit, which is a serious fire hazard.
Car Tuning Car Maintenance 3
What does it mean when your car's battery tests at 12.0V with the engine off?