Abstract: Heat exchanger comprising a cluster (10) of tubes in which a liquid coolant circulates, at least one collector reservoir (20) mounted at one end of the cluster, an expansion chamber (22) in communication with said collector reservoir at its bottom part and a liquid degasification passage connecting the collector reservoir (20) to the expansion chamber (22), this degasification passage comprising at least one tube (54) of the cluster (10) situated at a level below that of a transverse wall of the collector reservoir (20) as well as a conduit (60) which opens into the expansion chamber (22) and into the collector reservoir (20) facing and at some distance from the mouth (58) of the tube or tubes (54).

Abstract: An integrally molded water box (36) and expansion chamber (38) device having a water box (36) with a middle partition (40) dividing it into two compartments, with a liquid inlet fitting (44) opening into the top compartment and a liquid outlet fitting (46) opening out into the bottom compartment. The inlet fitting (44) is located adjacent to the middle partition (40) and is connected to the expansion chamber via an orifice (48) through a wall (50) separating the expansion chamber from the water box, said orifice forming a liquid degassing passage. The invention is applicable to motor vehicle radiators.