What does the engine coolant temperature gauge do?
The gauges on your dash are there to provide you with critical information while the vehicle is in operation. While some of them only work if the car is moving (your speedometer and tachometer, for instance), the engine coolant temperature gauge operates as long as the engine is running.
The gauge is comprised of a needle and a curve from “cold” to “hot.” During normal operation, the needle should stay somewhere in the middle. When you first start the engine, it will be at the cold mark, and slowly move to normal. However, if it moves into the hot range, you should stop the car as quickly as possible and turn off the engine – this indicates that it’s overheating.