Charge air cooler consists of liquid-cooled precooler and air-cooled main cooler

The invention relates to a charge air cooler composed of a liquid-cooled precooler and an air-cooled main cooler, wherein a multi-layer flat pipe for charge air is arranged between two distributor/collector units which are arranged on end sides and are provided with sealing plates, wherein flat tubes are spaced in parallel in a region of the pre-cooler via the flat tubes of the pre-cooler for thecoolant, which are in thermal contact therewith; the flat tubes are spaced in parallel in the region of the main cooler by means of outer laminations for cooling air, wherein the precooler is formed by a plurality of layers of flat tubes for the coolant, wherein the flat tubes forms a U-shaped flow channel along the horizontal direction; the flow channel has an inlet region for the coolant, a flowregion, a deflection region, a return region and an outlet region, wherein the inlet region and the outlet region of each layer of flat tubes are directly connected to each other in the vertical direction and are arranged on