A cooling module (1) comprises a first heat exchanger (3), which has a first pair of parallel manifolds (10, 11), and a second heat exchanger (4), which is in back-to-front relationship with the first heat exchanger (3) and has a second pair of parallel manifolds (7, 8) perpendicular to the first pair of manifolds (10, 11). The first pair of manifolds (10, 11) is fastened to the second pair of manifolds (7, 8) at four corners (13, 14, 15, 16) by means of four fasteners, of which the first is a rigid fastener (19), the second (20) and third (22) are two-way fasteners, and the fourth (27) is a four-way fastener. The four-way fastener (27) is situated at the corner (16) diametrically opposed to the corner (13) with the rigid faster (19), and the two-way fasteners (20, 22) are situated at one of the remaining corners (14, 15) each. The two-ways fasteners (20, 22) allow mutual movement only to and fro the rigid fastener (19), whereas the four-way fastener (27) allows mutual movement to and fro both of the two-way fasteners (20, 22).