Abstract: A tank device for a motor vehicle, and a motor vehicle having such a tank device. The tank device includes a motor vehicle tank, a ventilation outlet, and a filler pipe head configured to fill the motor vehicle tank. The filler pipe head includes a filler opening configured to receive a nozzle during a filling sequence, and a filling ventilation opening configured for movement between an open state during introduction of the nozzle to fluidically connect an inner space of the filler pipe head to the ventilation outlet, and a closed state during removal of the nozzle from the filler opening, the filler pipe head having an operational ventilation opening fluidically connected to the ventilation outlet, and which has a semi-permeable diaphragm to permit flow of gasses therethrough and also to prevent a flow of fluids.