A device for filling the crank case or transmission of an internal combustion engine with oil dispensed from a can opened by the device. The device comprises an outer casing, a cup member in the casing spaced from the side walls and bottom of the casing, registering openings in the cup member and casing bottoms, and a piercing and dispensing tube mounted in the cup member having a beveled piercing end facing upwardly in the cup member. Air passages are provided by the space between the cup member and casing communicating with the interior of the piercing tube. The tube is mounted in the cup member by a pin of magnetic material which has two functions: to attract ferrous matter and to separate the fluid flow momentarily, thereby allowing air passing upwardly or downwardly with the fluid, to mix with the fluid. The spacing means between the cup member and the casing may be a plurality of bars connected to the side walls of the cup member and having legs extending beyond the cup member bottom. A cover may be provided for closing the open tops of the casing and cup member when not in use.