A fastening between a fan shroud and a heat exchanger, the fastening including a plurality of cooperating fastening devices about the outer edge of the shroud and heat exchanger. At least one of the cooperating fastening devices comprises a locking hook on one edge of the shroud, a mount on an edge of the heat exchanger corresponding to the shroud one edge, a stop on the corresponding heat exchanger edge spaced from the mount slot in a direction opposite a first direction, and an elastically flexible extension on the locking hook including a locking tab. The mount defines a slot adapted to receive the locking hook from the first direction. The extension is elastically biased toward an interfering position between the locking tab and the stop when the locking hook is received in the mount slot, and is manually engageable to flex the extension to a releasing position in which the locking tab does not interfere with the stop.