A BMW engine's operating temperature will rise as you drive. Each engine has its own unique cooling system, designed to moderate the engine temperature so the car does not overheat. If a component of your cooling system fails, the engine is at risk of suffering permanent damage.
Engine Temperature Gauge
The engine temperature gauge is located in your BMW's instrument panel; it provides information about the engine's current operating temperature. It is marked by a thermometer symbol, and uses a needle to illustrate the vehicle's engine-temperature level. If the needle moves beyond the halfway mark on the gauge, your engine is beginning to overheat.
Water Pump Failure
Your BMW's water pump is an integral part of the cooling system. It is powered by a pulley and belt system. Open your BMW's bonnet and examine the belts that sit at the front of the engine. If any of these belts have snapped or are missing, your engine is likely overheating. Its cooling system is not receiving a steady flow of coolant.
Coolant Warning Light
A coolant-warning-light will illuminate on your BMW's on-board computer display when the engine-coolant level is low. If the engine is not receiving enough coolant, it will overheat. If the coolant-warning-light is illuminated in your instrument panel, your engine is likely going to overheat soon. Refill the coolant reservoir in your engine to restore the factory coolant level.