In a hollow-cast component, a core opening (13) created during manufacturing is closed with a closure piece (14). This closure piece is located inside a recess (15) in the component, whereby the recess is arranged so that it is imbedded completely in the cast material, and completely covers the core opening. Because of this installation, the closure piece is fixed in a form-fitting manner in the direction of two spatial axes, so that the closure piece only needs to be secured with an additional joint in the installation direction. It is preferred that the installation direction is normal in relation to the direction of maximal stress of the closure piece, so that a joint is subject to a relatively small stress and therefore can be produced with little expenditure and a high degree of operational safety.