Intercooler consisting of a liquid-cooled precooler and an air-cooled main cooler

An intercooler of a liquid-cooled precooler and an air-cooled main cooler, wherein between two distributor/collector units disposed at end sides with sealing plate several layers of flat tubes for charge air are disposed, wherein the flat tubes in the region of the precooler are spaced apart in parallel via flat tubes of the precooler in thermal contact with these flat tubes and that the flat tubes in the region of the main cooler are spaced apart in parallel via outer fins for cooling air wherein the precooler is developed of several layers of flat tubes for coolant, wherein the flat tubes form in the horizontal direction a U-shaped flow channel with an inlet zone, an onward-flow field, a deflection field, a return-flow field and an outlet zone for the coolant, wherein the inlet zones and the outlet zones of the individual layers of the flat tubes are directly connected with one another in the vertical direction and are disposed on one side on the intercooler and that the flat tubes for the coolant are disposed in the precooler in cross counterflow transversely to the flat tubes for the charge air.