Inspecting the 2014 Mazda Mazda3 Published on February 4, 2014 in Mechanical by Alain Morin Photo: Alain Morin Most of the air that enters the engine bay originates in the lower part of the bumper. In front of the radiator, there’s an interior grille that will prevent rocks from piercing it as well as shutters that close to help the engine heat up faster.