When your vehicle's temperature gauge reads "H," what does this mean?

When the temperature gauge on your vehicle reads "H," it indicates that the engine is overheating. This is a crucial warning signal that should not be ignored, as an overheated engine can lead to severe damage or even complete engine failure.

An engine that runs too hot may suffer from various issues, such as a blown head gasket, warped cylinder heads, or even the complete seizure of the engine. If you notice this warning, it is important to pull over safely and turn off the engine to allow it to cool, and then investigate the cause of the overheating, which could be due to a coolant leak, a failing thermostat, or a malfunctioning radiator.

Understanding this warning and responding appropriately is critical for the safety and longevity of your vehicle. The other answers do not accurately reflect the meaning of the gauge reading, as neither "the engine is running normally," "you need to increase speed," nor "oil needs to be changed" address the immediate and serious concern of engine temperature.