A method of forming a structural oil pan via lost core molding is disclosed. The structural oil pan comprises a bracket portion configured for mounting to the vehicle, a pan portion integrated with the bracket portion and defining an oil reservoir, and a structural section formed via lost core molding and defining a cavity. The method comprises the step of lost core molding by forming a metal core, molding the bracket portion and/or the pan portion about the metal core, and removing the metal core to form the structural section in at least one of the bracket portion and the pan portion. The method also includes co-molding the bracket portion and the pan portion together to form the structural oil pan.