Which option describes a sign of overheating that could indicate a fault?

• A. A cool engine block.
• B. Clean battery terminals.
• C. Visible signs of overheating that indicate faults.
• D. A low oil level.

Answer: (C)

Overheating shows up through observable indicators that the engine is running too hot and something in the cooling system isn’t working properly. The best choice describes visible signs of overheating that point to a fault, which is exactly what you’re looking for in a visual inspection: you’d look for things like steam or smoke from under the hood, coolant boiling or leaking, discolored or spattered coolant, damaged or warped hoses, or other noticeable damage in the cooling system. These signs directly signal that the engine is overheating and that a fault in the cooling system or engine could be present.

The other options don’t fit because a cool engine block isn’t overheating, clean battery terminals aren’t related to overheating, and a low oil level can contribute to overheating but isn’t itself a visible sign that overheating is currently occurring.