A heat exchanger, particularly for a motor vehicle, having a tube/fin bundle with tubes, through which a coolant can flow, and having at least one manifold into which the coolant, coming out of the tubes, can flow, whereby the at least one manifold has a manifold top part and a manifold bottom part, whereby outwardly extending protrusions, which form a passage geometry for receiving the tubes of the tube/fin bundle, are formed on the manifold top part and the manifold bottom part.