What Do the Three Numbers on the Water Temperature Gauge Mean?
2 Answers
Generally, the water temperature gauge has temperature values marked beside it, typically around 75°C, 90°C, and 120°C. Below is relevant information about the car's water temperature gauge: 1. Structure of the Water Temperature Gauge: Its sensor is a thermistor-type sensor fixed with threads on the engine's cooling water passage. The thermistor determines the current flowing through the coil windings of the gauge, thereby driving the needle to swing. 2. Introduction to the Water Temperature Gauge: The water temperature gauge displays the temperature of the cooling water in °C (Celsius). In the past, tap water was used as the cooling water for car engines, but now many engine cooling systems use specialized coolant, hence it is also called the coolant temperature gauge. Some water temperature gauges use indicator lights; when the water temperature light is on, it indicates that the temperature is too high.
When I first started driving, I was also curious about those numbers on the coolant temperature gauge, like the common 50, 90, and 120. They are actually the temperature scale in degrees Celsius for the engine coolant. 50°C represents the cold start temperature, where the needle sits when the car is just started; 90°C is the ideal operating temperature, where the engine runs most efficiently; and 120°C is the warning zone, indicating overheating risk. While driving, the needle should steadily rise to around 90°C and stay balanced there. If the needle shoots toward 120°C, it means the engine is running too hot, possibly due to a faulty fan or coolant leak. In such cases, it’s best to stop the car, turn off the engine, and check the cooling system. Prolonged overheating can damage engine components like the cylinder head. So, keeping an eye on these number changes helps detect issues early and avoid major repairs. During regular maintenance, ensuring the coolant is at the proper level and the radiator is free of debris will keep the temperature gauge happily in the normal range.
