What does a working muffler do for your vehicle?
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A.
Cools the engine when it overheats
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B.
Filters smoke and excessive noise Correct
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C.
Redirects exhaust fumes into the passenger area
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D.
Boosts fuel economy at highway speeds
The answer is "Filters smoke and excessive noise"
The manual says every motor vehicle must have a muffler in good working order, and that the muffler filters smoke and excessive noise. Drivers who pick cooling the engine are reaching for the radiator, a separate hot part connected by pipes that handles temperature, not sound and emissions.
The traps in the wrong answers
A. Cools the engine when it overheats
Cooling the engine is the radiator's job; the muffler filters smoke and excessive noise. Confuses the muffler with the radiator because both are hot parts with pipes running to and from them.
C. Redirects exhaust fumes into the passenger area
The exhaust system carries fumes to the rear of the vehicle to be released; fumes reaching the cabin is a sign of a leak, which the manual says to check for often. Treats the smell of exhaust inside an older car as how the system is designed to work, rather than as the leak the manual flags.
D. Boosts fuel economy at highway speeds
Fuel economy comes from habits like proper tire pressure and smooth starts, not from the muffler, whose job is filtering smoke and excessive noise. Carries the Drive Green fuel-saving habits over to the muffler, which handles sound and emissions instead.
This question tests your knowledge of Vehicle Equipment in North Carolina. Source: North Carolina Driver Handbook, "Muffler and Exhaust System," p.67..
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