A heat exchanger is provided that includes a first tube/fin block, first headers arranged on both sides of the first tube/fin block, which first headers communicate with the tubes of the first tube/fin block, and a second tube/fin block having second headers arranged on both sides of the second tube/fin block, which second headers communicate with the tubes of the second tube/fin block, wherein the first tube/fin block having the corresponding first headers is an air-cooled low-temperature coolant cooler and the second tube/fin block having the corresponding second headers is an air-cooled refrigerant cooler, wherein the headers of the first tube/fin block arranged on a respective side of the tube-fin block and a header of the second tube/fin block are connected to one another.