What is a common reason for engine overheating?

A defective fan clutch can lead to engine overheating because the fan plays a critical role in cooling the engine by drawing air through the radiator. When the fan clutch malfunctions, the cooling fan may not engage or may not spin at the appropriate speed, which prevents the proper airflow needed to dissipate heat from the engine and radiator. This results in an inability to maintain optimal operating temperatures, leading to overheating.

In contrast, a stuck open thermostat would typically prevent the engine from reaching the proper operating temperature, leading to poor fuel efficiency and performance rather than overheating. Using low-quality oil can result in inadequate lubrication, potentially causing engine damage but not specifically leading to overheating as a direct cause. Finally, using the incorrect spark plug type would affect ignition and combustion efficiency, but it would not directly lead to overheating issues in the engine. Each of these alternatives illustrates mechanisms that affect engine performance, but the defective fan clutch directly relates to the cooling system’s efficiency, which is crucial for preventing overheating.