Abstract: A tank assembly utilized in a heat exchanger such as a radiator and the method of connecting a cylindrical spout such as a filler tube in an opening in the tank wall. An opening is formed in the tank wall with a skirt extending inwardly from the tank wall. A plurality of cam/lock sections are formed at the lower extremity of the skirt with each cam/lock section having a cam surface leading from a receiving end to a locking recess, the opposite wall of which is extended to define a stop. A plurality of radial slots are formed in the tank wall to extend radially of the skirt adjacent the receiving ends of the cam surfaces. A spout is formed having a radially extending shoulder and a lower portion with a plurality of radially extending tabs. An annular seal recess is disposed in the tank wall for receiving a seal.