Which item must discharge to the outside of the vehicle?

The exhaust system is designed to direct harmful gases produced by the engine out of the vehicle and into the atmosphere. This is essential for maintaining a safe and healthy environment inside the vehicle, as these gases can be toxic if allowed to accumulate. The exhaust system includes components such as the exhaust manifold, catalytic converter, muffler, and exhaust pipes, all of which work together to channel exhaust gases, reduce noise, and minimize emissions. Proper discharge to the outside is crucial for both vehicle performance and compliance with environmental regulations.

In contrast, the other items mentioned serve different functions and are not intended to discharge outward. Fuel lines transport gasoline or diesel to the engine but are sealed to prevent leaks and contamination. Engine coolant circulates within the cooling system to maintain optimal engine temperatures, but it is contained within the system and not meant to escape outside the vehicle. Batteries provide electrical power and contain hazardous materials; their contents should be kept within the battery casing and handled properly to avoid leaks.