The intervals of replacing the air filter stated are assumed for normal driving conditions, if however, the vehicle is mostly driven in conditions that include dusty environment then the air filter should be changed often. For removing the upper air filter housing simply release the clamps of the mass air flow sensor and the upper air filter housing clips. Subsequently, pull out the cover and insert a new air filter. During the installation remember to retain the O-ring for the mass air flow sensor in the upper air filter housing cover.