At what temperature does the BMW thermostat open?
2 Answers
There is no standard opening temperature. The electronic thermostat is controlled by the DME (engine control unit), which determines when to open based on various parameters, such as: ambient temperature, engine coolant temperature, cabin heating temperature, electric water pump speed, transmission oil temperature, etc. Location of the BMW thermostat: The thermostat in BMW vehicles is located at the lower right side of the engine, near the water pump. Introduction to the thermostat: When the coolant temperature is below the specified value, the refined paraffin inside the thermostat's temperature-sensitive body remains solid, and the thermostat valve closes the passage between the engine and the radiator under the action of the spring, causing the coolant to return to the engine via the water pump.
Over the years of driving BMWs, I've noticed that the thermostat typically activates when the engine temperature reaches around 85 degrees Celsius, at which point the coolant starts flowing to the radiator. If it opens too early or too late, the engine may overheat or warm up too slowly, affecting performance. For example, during cold starts in winter when the temperature hasn't reached 85 degrees, the coolant circulates only within the engine to speed up the warming process. Once it hits 85 degrees, the valve opens to allow the system to cool down. Variations among BMW models might cause the activation point to fluctuate between 80-90 degrees, but 85 degrees is the standard value. It's advisable to regularly check the thermostat. If you notice the temperature gauge fluctuating or hear unusual engine noises while driving, the thermostat might be stuck. Maintaining the coolant by changing it every two years can prevent blockages and rust, extending the lifespan of components.