
BMW X3's original air filter is Mann-Filter. Function of the air filter: To filter out particulate impurities from the air. When the engine is running, it needs to draw in a large amount of external air. The air filter removes 'inhalable particles' from the air, which then enters (the intake manifold or) the cylinder to mix with gasoline for combustion. If the air filter fails to perform its intended filtering function, larger particles in the air will enter the engine and combust, leading to various 'faults,' such as the commonly mentioned carbon deposits and engine cylinder scoring. Location of the air filter: The air filter is located in the engine compartment. By unscrewing seven fixing screws and lifting the box, the air filter can be removed.


