Why does the BMW 3 Series display a low coolant warning?
1 Answers
Low coolant means the coolant level is below the normal level, and the cooling system needs to be inspected. Thermostat failure: The thermostat is a component that automatically acts as a valve based on the engine's water temperature. It is usually installed at the outlet of the radiator and the inlet of the water pump. When the coolant temperature is low, the thermostat blocks the low-temperature coolant from the radiator, preventing it from entering the engine water jacket. This allows the water temperature in the jacket to rise quickly. When the water temperature reaches a certain level, the valve gradually opens, allowing the coolant from the radiator to circulate again. This coolant flows through the radiator, slowly increasing the water temperature while dissipating heat into the atmosphere, maintaining the engine's water temperature at an appropriate level—this is known as the major circulation. If the thermostat malfunctions and the valve cannot close, the coolant remains in the major circulation, potentially causing the engine's water temperature to drop too low. Alternatively, some vehicles may have their thermostats removed during summer to lower the temperature, which can also result in very low engine water temperatures. Radiator fan running continuously: Another issue is the radiator fan. For electric fans, circuit faults can cause the fan to run continuously. For viscous fans, a faulty viscous clutch can also lead to continuous fan operation. These issues can result in abnormally low water temperatures.
