A valve unit for a motor vehicle having a valve housing, which includes a valve inlet and a valve outlet, and having a valve body disposed in the valve housing, which includes a cross-section, increasing up to an inflection point and decreasing once past the inflection point, and which is guided from a closed position in which the valve body seals the valve inlet to a final opened position in which the valve body abuts a stop element fixed in the valve housing, releasing the valve inlet, and in which an inflow section is formed between the valve inlet and the inflection point of the valve body, and an outflow section is formed between the inflection point of the valve body and the valve outlet.