Which of the following is a common indicator of overheating?

One of the primary indicators of an engine overheating is an engine temperature gauge reading above normal. This gauge typically provides real-time information about the engine’s operating temperature. When the gauge shows readings that exceed the normal operating range, it signals that the engine is becoming excessively hot.

Overheating can result from various issues, such as low coolant levels, a malfunctioning thermostat, or a failed water pump, among others. Monitoring the temperature gauge is critical for preventing engine damage, as prolonged overheating can lead to severe consequences, such as warped cylinder heads or a blown head gasket.

The other options relate to different problems; for instance, dark tailpipe smoke may indicate fuel richness or combustion issues rather than overheating. Increased coolant levels could suggest an internal leak, while no change in engine sound may not reflect any issues at all. In contrast, an abnormal reading on the temperature gauge provides a direct and actionable warning related to the thermal state of the engine.