Abstract: A heat transfer device for a motor vehicle includes a rib/tube block arranged between two collection containers. The tube ends of the fin/tube block are widened in the area of each collection container and are then brought together flat into end packets. Both collection containers are set flush to a respective tube end packet and brazed hermetically to the same. At least one collection container is provided with at least one partition wall that divides the collection container. The partition wall has an outer contour that corresponds to the inner contour of the wall of the collection container. As a result, the partition wall can be soldered hermetically around the inner contour. A holding leg is provided on the partition wall and is inserted over two adjacent wall sections of neighboring tube ends of the tube end packet. One use of the device is as a water/air radiator.