How often should oil in a commercial vehicle be changed?

Answer: B — Every 5,000 to 10,000 miles

The correct answer, which suggests changing the oil in a commercial vehicle every 5,000 to 10,000 miles, aligns with standard maintenance practices for heavy-duty engines. Regular oil changes help ensure that the engine runs smoothly and efficiently by preventing the buildup of contaminants and maintaining optimal lubrication. Engines operate under different stresses compared to standard passenger vehicles, and thus they require more frequent oil changes to protect against wear and tear. The 5,000 to 10,000-mile range reflects a balance between too frequent changes, which could lead to unnecessary maintenance costs, and too infrequent changes, which could lead to engine damage. This approach is also supported by manufacturers' recommendations, which often provide specific intervals based on engine type, usage, and conditions. Additionally, factors such as driving conditions (stop-and-go traffic, extreme temperatures, or heavy loads) can influence how often oil should be changed within that range. Regular oil changes are crucial for maintaining engine health and ensuring compliance with maintenance schedules to avoid costly repairs or downtime.