Crankcases, typically cast aluminum or iron, form the structural base of the engine, enclosing the crankshaft, pistons, and connecting rods. They provide mounting points for vital engine accessories and maintain oil containment within the lower engine block. Integral oil passages and baffling are cast into the crankcase to facilitate lubrication and prevent oil starvation during vehicle maneuvers. Multi-piece designs utilize gasketed mating surfaces for sealing, while unitized construction incorporates direct machining of bearing bores. Crankcases are fundamental to both gasoline and diesel engines across most vehicle platforms.