What to Do If the Coolant Temperature Is Too Low?
2 Answers
The cause of excessively low coolant temperature is generally a damaged thermostat that prevents it from closing, or a malfunctioning cooling fan that remains constantly running. Below is a detailed explanation regarding excessively low coolant temperature: 1. Causes of excessively low coolant temperature: The louver is stuck in the fully open position, the fan clutch is sintered, the electric fan runs continuously, the ambient temperature is too low, or the coolant temperature gauge or sensor is faulty. 2. Diagnosis and troubleshooting: ① Check the performance of the thermostat and replace it if it does not meet requirements. ② Inspect the operation of the louver. If it does not close tightly or cannot close, maintenance and repair are required. ③ For engines without a fan clutch or electric fan, observe the fan after starting. If the fan starts running immediately upon engine start, the fault lies with the electromagnetic coil, temperature sensor, motor, or fan clutch. In such cases, further inspection is necessary. ④ When the ambient temperature is too low, an insulation curtain should be added. ⑤ Replace the temperature sensor and coolant temperature gauge if they are damaged.
Having driven for over 20 years, I've found that the most common cause of excessively low coolant temperature is a thermostat issue. It gets stuck in the open position, allowing coolant to circulate too quickly and preventing the engine from warming up. Especially during cold winter starts, the temperature gauge doesn't budge at all, which can be really frustrating. My suggestion is to not turn off the engine immediately—let it idle for a few minutes first. If possible, drive slowly at no more than 40km/h to help the engine warm up. Also check the coolant reservoir—don't just look at the fluid level, but unscrew the cap to inspect the liquid's clarity. If it appears cloudy or has impurities, it's time for a change. Another method is to check the thermostat's operating temperature—for most regular cars, it should close to restrict flow around 90°C. Low engine temperature leads to improper combustion, significantly increased fuel consumption, accelerated carbon buildup, and component wear. Long-term neglect can result in expensive repairs. If you're unable to inspect it yourself, visit a repair shop promptly to replace the thermostat—never delay, as safety comes first.
