Abstract: A heat exchanger tank for connection to a header part to form a heat exchanger manifold has an elongate trough-shaped body 4 having opposed side walls 14,16; and at least one strengthening tie bar 36 extending between the side walls 14,16, the tie bar comprising an elongate body 37 having enlarged head portions 40 at opposite ends thereof which are of generally wedge-shaped section of dimension which decreases in a direction generally perpendicular to the elongate extent of the body of the tie bar, with the tank side walls 14,16 defining opposed pockets 44 for of shape which corresponds to the shape of the head portions for receiving therein respective head portions of the tie bar.