Why is the temperature gauge normal when the thermostat is broken?

[AryaDella]

Thermostat damage temperature gauge normal reason is thermostat protection water temperature does not drop: The following is the relevant content introduction: 1. The working principle of the thermostat: The thermostat automatically adjusts the amount of water entering the radiator according to the temperature of the cooling water, changes the circulation range of the water, and adjusts the heat dissipation capacity of the cooler to ensure that the engine works within a suitable temperature range. The thermostat must maintain good technical condition, otherwise it will seriously affect the normal operation of the engine. 2. The role of the thermostat: to prevent the engine from being too cold. After the engine is working normally, when driving at high speed in winter, if there is no thermostat, the engine temperature may be too low. The engine needs to temporarily terminate the water circulation to ensure that the engine temperature is not too low.

[JuliannaRose]

After driving for so many years, I've often encountered thermostat failures stuck in the open position, causing the coolant to continuously circulate in the large loop. The engine temperature simply can't rise, hovering around 60°C or so. The temperature gauge is driven by the coolant temperature sensor, which only detects the current water temperature. As long as the sensor isn't faulty or is in the right position, the gauge will faithfully display that low temperature, making everything seem perfectly normal. But the hidden dangers are huge: prolonged low engine temperature increases oil viscosity, reducing lubrication on cylinder walls and accelerating wear; incomplete fuel combustion leads to skyrocketing fuel consumption and potential carbon buildup; in winter, the heater won't even blow warm air. In short, the normal-looking temperature gauge is an illusion—your car's actual condition is deteriorating. Don't delay; get it fixed ASAP.

[McJoseph]

As a car enthusiast, I found the thermostat was broken while repairing my own car, but the temperature gauge still showed normal readings. This is because the coolant temperature sensor directly measures the actual temperature of the coolant. With the thermostat stuck open, the coolant flows too fast and the temperature stays low, so the sensor detects the low temperature and the gauge displays it accordingly. However, the risks shouldn't be ignored: the engine won't reach its ideal operating temperature range, leading to reduced power output and sluggish acceleration; prolonged operation in this condition accelerates component wear, resulting in higher repair costs. Simply put, a normal gauge reading doesn't mean everything is fine—paying attention to changes in power while driving is key. Regular maintenance can prevent such minor issues from turning into major problems.

[RafaelDella]

When I was helping out at the auto shop, the technician explained the reason for a faulty thermostat but normal temperature gauge readings quite simply: The temperature gauge is controlled by an independent temperature sensor, which is installed on the cooling system to provide real-time readings. If the thermostat is stuck open, the coolant circulates too quickly and can't heat up properly, so the sensor measures this low temperature and transmits it to the gauge, which then displays a normal low reading. However, this means the engine can't warm up to the optimal 90-degree point, leading to poor lubrication. Driving for extended periods under these conditions can increase wear and fuel consumption. The advice is not to rely solely on the gauge for safety—combine it with driving experience and get it checked promptly.