A heat exchanger for transferring heat between a gaseous first fluid and a liquid second fluid, - having multiple pipes which extend through a first fluid path for conducting the first fluid, said pipes externally being coupled in heat-transmitting fashion to cooling fins which are arranged in the first fluid path and through which the first fluid can flow and said pipes internally forming a second fluid path for conducting the second fluid, - wherein the pipes and the cooling fins are stacked on one another in a stacking direction in order to form a cooler block, said stacking direction extending transversely with respect to a main flow direction of the first fluid in the first fluid path, - wherein the cooler block has, on two outer sides facing away from one another in the stacking direction, in each case one side part for lateral delimitation of the first fluid path, - wherein the two side parts are fixedly connected to one another by means of at least one tension rod which is a component separate from the cooling fins and the pipes and which permits a transmission of tensile force in the stacking direction, - wherein the respective tension rod extends only over a relatively small portion of the width of the cooler block in a width direction of the cooler block, which runs transversely to the stacking direction and transversely to the main flow direction of the first fluid, characterized in that - at least one such tension rod is arranged externally on the cooler block on an inflow side of the cooler block with respect to the first fluid path or on an outflow side of the cooler block with respect to the first fluid path and connects the two side parts with one another, - that at least one such tension rod is configured in a comb-like manner, so that it has a base running parallel to the stacking direction and at least three prongs (35, 36) projecting from the base parallel to the main flow direction of the first fluid, - that two exterior prongs, remote from one another, overlap the two side parts, whilst at least one interior prong engages into the cooler block. - having multiple pipes which extend through a first fluid path for conducting the first fluid, said pipes externally being coupled in heat-transmitting fashion to cooling fins which are arranged in the first fluid path and through which the first fluid can flow and said pipes internally forming a second fluid path for conducting the second fluid, - wherein the pipes and the cooling fins are stacked on one another in a stacking direction in order to form a cooler block, said stacking direction extending transversely with respect to a main flow direction of the first fluid in the first fluid path, - wherein the cooler block has, on two outer sides facing away from one another in the stacking direction, in each case one side part for lateral delimitation of the first fluid path, - wherein the two side parts are fixedly connected to one another by means of at least one tension rod which is a component separate from the cooling fins and the pipes and which permits a transmission of tensile force in the stacking direction, - wherein the respective tension rod extends only over a relatively small portion of the width of the cooler block in a width direction of the cooler block, which runs transversely to the stacking direction and transversely to the main flow direction of the first fluid, - at least one such tension rod is arranged externally on the cooler block on an inflow side of the cooler block with respect to the first fluid path or on an outflow side of the cooler block with respect to the first fluid path and connects the two side parts with one another, - that at least one such tension rod is configured in a comb-like manner, so that it has a base running parallel to the stacking direction and at least three prongs (35, 36) projecting from the base parallel to the main flow direction of the first fluid, - that two exterior prongs, remote from one another, overlap the two side parts, whilst at least one interior prong engages into the cooler block.