Heat exchanger in which first projections (20,22) are formed on the face plate of the tank (10) which stand out from the plate and extend in the direction of the layer arrangement. Second projections (21,23) are formed on the face plate of the tank which stand out from the plate and are arranged between neighbouring openings on opposite sides of the first projections. A tolerance groove (19) extending in the direction of the layer arrangement is formed on the inner side of the plate opposite the first projections, allowing the dividing element (11) to be inserted into the groove.
