Abstract: A heat-exchanger tank consisting of a cover and a plate (5) fixed at the opening of the cover, the plate (5) being elongate and U-shaped, having a web portion (20) and two flanges (21, 22); and the cover consisting of a U-shaped middle piece (2) fixed with its flanges (18, 19) to the plate flanges, and two separately manufactured cup-shaped end pieces (3, 4), the mouths of which are U-shaped for connection to the respective end of the middle piece (2); and the end piece (3, 4) having two guide flanges (12, 13) connected to the flanges (21, 22) of the plate and arranged so as, when the heat-exchanger tank is mounted, to guide the end pieces (3, 4) into correct alignment with the middle piece (2).