What to Do When the Car Temperature Gauge Shows High Readings?
2 Answers
Reasons for abnormally high readings on the car temperature gauge include dirt on the contact surface between the temperature sensor and coolant; aging of the thermistor; abnormal operation of the voltage regulator; short circuit in the temperature gauge heating coil; and instability of the thermostat sensor, which may cause the temperature gauge to fluctuate between high and low readings. Additional information is as follows: 1. Temperature Gauge: The temperature gauge displays the temperature of the coolant in degrees Celsius. Its sensor is a thermistor-type sensor, fixed with threads on the engine coolant passage. The thermistor determines the current flowing through the coil windings of the temperature gauge, thereby driving the pointer to move. 2. Hazards of Overheating: Overheating poses the greatest risk. Even if the car does not have a temperature gauge, it will have a temperature warning light. When the temperature is too high, the warning light will illuminate, prompting the driver to stop and inspect the vehicle, so overheating can be detected even without a temperature gauge. Additionally, if the warning light is not noticed, overheating is usually accompanied by boiling over, where a large amount of coolant spills from the reservoir and white steam emerges from the engine. Stopping the car at this point is still not too late. Whether or not the car has a temperature gauge, drivers should always pay attention to warning lights on the dashboard. If a red warning light comes on, the car must be stopped immediately.
I've encountered the issue of a falsely high coolant temperature gauge several times, especially noticeable during long-distance driving. The root cause is usually a faulty coolant temperature sensor—either due to aging or contamination, leading to incorrect readings. Alternatively, it could be an internal circuit issue in the dashboard displaying inflated values. A falsely high reading might make you complacent while the engine could actually be overheating, risking blown head gaskets or severe engine damage at great cost. My advice: pull over immediately to check the coolant level—wait for the engine to cool, then open the reservoir cap to inspect. If low, top it up; if normal, restart the vehicle to see if the gauge still reads high. If it persists, do NOT continue driving—head to a professional auto shop for sensor diagnostics or gauge replacement. During routine maintenance, remind technicians to clean the sensor contacts to prevent dirt buildup. Proper cooling system upkeep can save you from major repairs.
