A heat exchanger including a core with tubes and ribs between tube plates, two collecting tanks on the tube plates, and closure caps, all produced from solder-coated aluminum. The core includes a plurality of alternating flat tubes and ribs between spaced tube plates. Each collecting tank has two longitudinal walls joined to the longitudinal connection edges of one of the tube plates. The closure caps close ends of the collecting tanks, and have an edge aligned substantially parallel to the collecting tank walls. The edges of the longitudinal walls of the collecting tanks are arranged between the longitudinal connection edges of the tube plates, with protrusions on the edges of the longitudinal walls inserted in openings in the tube plates. The transverse connection edges of the tube plates have a contour cut-out matching the closure cap profile to form a tight and strong solder bond with the closure caps.