Heat exchanger, especially for motor vehicle

The invention relates to a heat exchanger for heat exchange between at least a first fluid and a second fluid, in particular for a motor vehicle: - the heat exchanger comprising a heat exchange core with an alternating stack: • exchange tubes thermal (5) having flow channels (7) for the first fluid, and • dividers (15), and - the heat exchanger having at least partially a coating capable of melting when joining by brazing. According to the invention: - the spacers (15) have respectively at least one reservoir (154) adapted to collect the coating during brazing of the heat exchanger (1), - each container (154) being arranged on one end of a spacer (15) and facing an end of a heat exchange tube (5), so as to prevent the clog of coating said at least one flow channel (7) during brazing of the heat exchanger .