What is the primary benefit of a properly serviced air cleaner?

The primary benefit of a properly serviced air cleaner is that it prevents dust particles from damaging internal engine parts. Air cleaners are crucial components in an engine’s intake system; they filter out contaminants such as dirt, dust, and other debris from the air entering the engine. If the air cleaner is clogged or dirty, these harmful particles can enter the engine, potentially causing wear and tear on vital components like the cylinders, pistons, and valves. Over time, this damage can lead to decreased engine performance and even catastrophic engine failure.

While enhancing fuel efficiency is certainly a significant benefit of a clean air filter, it is a secondary effect rather than the primary benefit. Clean air allows for optimal combustion, which can improve fuel efficiency, but the foremost role of the air cleaner is to protect the engine's internal mechanisms. Other options such as reducing engine noise and increasing acceleration speed are not directly tied to the function of an air cleaner and tend to depend on various other factors within the engine's design and operation. Therefore, the correct answer emphasizes the protective role of the air cleaner, which is paramount for maintaining engine health.