A coolant warning light typically indicates an abnormality in one of the three core components of the cooling system: circulation, coolant level, and sensors. Specifically, the causes can be categorized into three types: insufficient coolant, obstructed circulation, and component failure.

Insufficient coolant may stem from natural depletion without timely replenishment, or from leaks in pipes, the radiator, or the water pump. Natural depletion often occurs with prolonged use and a lack of regular checks and replenishments, while component leaks can involve multiple points. For example, after prolonged exposure to high temperatures, the rubber material in water pipes can age and crack, leading to coolant leakage; a weakened seal in the radiator can also cause slow leaks. Owners can routinely check for coolant residue on the ground and observe whether the coolant level in the expansion tank is below the minimum mark to initially determine if there is a leak.

Obstructed circulation may be caused by a clogged radiator, a malfunctioning thermostat (preventing the switch to the main circulation loop), or insufficient water pump pressurization, resulting in poor coolant flow. As a critical component for heat dissipation, the radiator, if not cleaned regularly over a long period, can become clogged with external dust, catkins, and other debris, while internally, scale buildup can impede coolant flow. The thermostat, acting as a "switch" controlling coolant circulation, will remain in a small circulation loop if it malfunctions, hindering effective heat dissipation and leading to overheating and triggering an alarm. The water pump, the power source for coolant circulation, will suffer from insufficient pressure if its impeller is damaged or bearings are worn, slowing or halting coolant circulation.

Regarding component failures, the coolant level sensor directly monitors the coolant level. Damaged internal components or loose/short-circuited wiring can transmit incorrect low-level signals to the vehicle's computer, causing false alarms. A malfunctioning radiator fan directly impacts cooling efficiency. A damaged fan motor or control module can prevent timely activation when coolant temperature rises, preventing heat dissipation and causing a rapid temperature increase that triggers an alarm. Additionally, a faulty coolant temperature sensor in some vehicles may also incorrectly report a high-temperature signal, illuminating the warning light.

When the coolant warning light illuminates, the driver should immediately reduce speed and pull over to a safe location to avoid prolonged engine operation at high temperatures. If the coolant level is found to be below the minimum mark, add coolant of the same specification to the normal range and observe whether the warning light clears. If the coolant level is normal but the warning light persists, or if there is obvious leakage or component damage, avoid continuing to drive and contact a professional mechanic for repairs to ensure the vehicle's normal operation and driving safety.