Cap for a container, especially a vehicle radiator

A closure cap for a container such as a vehicle radiator having an opening to be closed by said cap, said cap having a central axis and comprising an outer part, an inner part connected with said outer part and insertable into said opening, said inner part having a pressure compensation channel running therethrough, and an overpressure valve arranged in said inner part for opening and closing said pressure compensation channel, said overpressure valve having an axially movable first valve body having a firs ring-shaped substantially radially extending sealing surface, and a second valve body axially movable between two end positions and having a ring-shaped first countersealing surface ad an opening radially inside of said firs countersealing surface, mean for biasing said sealing surface of said first valve body against said ring-shaped first countersealing surface of said second valve body, said second valve body also having radially outside of said first countersealing surface a second ring-shaped sealing surface facing inwardly toward the interior of said container when said cap is attached to said container and having a third ring-shaped sealing surface facing outwardly away from the interior of said container said inner part providing second and third countersealing surfaces cooperable respectively with said second and third sealing surfaces, said first and second valve bodies being so constructed and arranged that a respective one of said second and third sealing surfaces in each of said two end positions of said second valve body lies against the respectively associated one of said second and third countersealing surfaces provided by said inner part.