What maintenance step helps to ensure efficient performance of the engine's cooling system?

Maintaining the engine's cooling system is critical for efficient performance, as it helps to regulate the engine's temperature and prevent overheating. Regularly checking and flushing the coolant system is vital to ensure that the coolant can effectively absorb and dissipate heat. Over time, contaminants and debris can accumulate in the coolant, which can lead to clogs or reduced effectiveness in temperature regulation. Flushing the system removes these impurities and replenishes the coolant with fresh fluid, enhancing the overall cooling performance and extending the life of the engine components.

While regularly changing the engine oil helps maintain engine performance and longevity, it doesn’t directly address the cooling system's effectiveness. Upgrading the engine type and only inspecting the radiator might improve performance under certain conditions, but these actions do not reflect the comprehensive maintenance necessary for the entire cooling system. Thus, focusing on the coolant system through regular checks and flushes is the most effective maintenance step for ensuring optimal engine temperature management and performance.