BMW radiator grille evolution. BMW kidney shape radiator cover – called often ‘BMW grille‘, is since 1932 one of the characteristics of the brand. Of course, there are many other traditional features of the BMW cars, but the ‘grille’, often imitated by other brands, is a truly recognizable feature of the BMWs. It had much to do with the construction of these cars: motor at the front, radiator just behind the grille, transmission in the middle, wheels powered at the rear.