Patent ID: 6932232

Claim:
A radiator cap with pressure valve comprising: a cap body, said cap body including: an upper member in the form of an upper lid having at its upper end a small-diameter pipe for guiding cooling water; a cylindrical lower member separate from said upper member, said lower member having at its lower end inner periphery a valve seat in the form of an inner flange, the upper side of said lower member being secured to said upper member; and a sealing material mounted on the outer periphery of said lower member or said upper member to provide a liquid tight sealing between said lower member or said upper member and a filler neck disposed at the upper end of a radiator tank; a pressurization valve internally mounted in said cap body so as to be pressed against said valve seat by way of a pressure spring; and a negative pressure valve positioned centrally of said pressure valve, wherein with said pressurization valve internally mounted and said lower member firmly secured to said upper member, said cap body is inserted into said filler neck and fastened thereto in an anti-disengagement manner by use of locking means; and said locking means comprising: inverted-L-shaped locking grooves formed integrally on the outer periphery of said lower member of said cap body, said locking grooves extending axially from the lower edge of said lower member and circumferentially from the upper end of said lower member; and raised portions formed on the inner periphery of said filler neck at positions in registration with said locking grooves, said raised portions being guided along said inverted-L-shaped grooves so that said cap body is fastened to said filler neck in an anti-disengagement manner.