Ford Fiesta Grilles Available Here. Grilles are double-duty car parts, contributing both function and style to your vehicle. On the functional side, they help keep debris from getting into the engine compartment and potentially causing costly wear or damage. Grilles also let air into the engine compartment, playing an important role in preventing engine overheating. Grilles aren’t only about function: They also complete the look of your vehicle so a damaged or missing grille can quite a negative impact on the appearance of your car. It's important to note that the vast majority of grilles are not supplied with the vehicle manufacturers badge.