Abstract: In a closure cap for a container, especially for a vehicle radiator, with an outer part (12), an inner part (16) of cup-shape connected with the outer part and insertable into the opening to be closed, and having an overpressure valve arranged in the inner part for opening and closing a pressure compensation channel running through the inner part (16), which overpressure valve includes an axially movable first valve body (26) which carries a first ring shape substantially radially extending sealing surface (36) biased against a ring-shaped first countersealing surface (48) by a spring urging the first valve body toward the bottom of the inner part (16), the first outwardly directed countersurface (48) is formed by a second valve body (46) movable axially between two end positions, which second valve body has an opening radially inside of the first countersealing surface (48) and radially outside of the first countersealing surface has an inwardly facing second ring-shaped sealing surface (52) and an outwardly