Cover for a heat exchanger bundle

A cover for attaching to a housing of a heat exchanger, the cover comprising a wall for closing off an orifice for introducing a heat exchange core into the housing, the wall being configured to allow the cover to be attached removably to the housing and having a raised edge, the cover also comprising means for mechanical reinforcement of the wall, wherein the means for mechanical reinforcement comprises at least two identical structures, wherein each identical structure comprises at least one mechanical strengthening rib central to each structure having a long length, a short length and a thickness, wherein each mechanical strengthening rib includes at least two protrusions along the long length of each mechanical strengthening rib, wherein each protrusion is at a right angle respective to the long length and is identical in shape and orientation, wherein one of the at least two protrusions is on the right side of the long length and the other of the at least two protrusions is on the left side of the long length together forming a cross shape with the long length.