The BMW f30 thermostat is in the thermostat housing at the decrease coolant line. The thermostat is what measures the temperature of the coolant walking thru the road</br> and from there it can decide what temp the engine is running at. If this element isn't always operating then the engine runs the threat of overheating</br> which is awful for the auto. If an engine overheats it will run the chance of warping or cracking the top gasket</br> so that it will value lots to repair in the end. In case you get a check engine light telling You that the thermostat isn't working then get it constant right away. It's far simplest approximately 200 for a complete substitute so that you do no longer need to wait.