A fan with a rotor and a fan impeller , wherein the rotor is rotatable about an axis of rotation (A) and has a connecting portion , wherein the fan impeller has a fastening portion corresponding to the connecting portion and, with the fastening portion on the connecting portion , is centered by means of at least one centering element relative to the rotor and fixed to the rotor by means of at least one fastening element , wherein the fastening element is a screw with a screw head , a threaded portion , and a shaft that is arranged between the threaded portion and the screw head , a spacer sleeve being arranged around the shaft whose outer diameter is smaller than an outer diameter of the screw head and whose thickness (H3) is smaller by a predetermined amount than a thickness (H2) of the fastening portion , wherein a thread corresponding to the fastening element or an opening corresponding to the fastening element is respectively formed in the connecting portion , and a through opening corresponding to the spacer sleeve is respectively formed in the fastening portion , and wherein the fastening portion is also made of a characteristically deformable material, so that when the screw is screwed into the thread , the spacer sleeve is guided into the through opening , a predetermined preload force of the screw is supported via the spacer sleeve against the connecting portion , and the fastening portion is clamped to the connecting portion in an area adjoining the through opening in which the screw head rests against the fastening portion , wherein the spacer sleeve is held by the screw on the shaft . wherein the rotor is rotatable about an axis of rotation (A) and has a connecting portion , wherein the fan impeller has a fastening portion corresponding to the connecting portion and, with the fastening portion on the connecting portion , is centered by means of at least one centering element relative to the rotor and fixed to the rotor by means of at least one fastening element , wherein the fastening element is a screw with a screw head , a threaded portion , and a shaft that is arranged between the threaded portion and the screw head , a spacer sleeve being arranged around the shaft whose outer diameter is smaller than an outer diameter of the screw head and whose thickness (H3) is smaller by a predetermined amount than a thickness (H2) of the fastening portion , wherein a thread corresponding to the fastening element or an opening corresponding to the fastening element is respectively formed in the connecting portion , and a through opening corresponding to the spacer sleeve is respectively formed in the fastening portion , and wherein the fastening portion is also made of a characteristically deformable material, so that when the screw is screwed into the thread , the spacer sleeve is guided into the through opening , a predetermined preload force of the screw is supported via the spacer sleeve against the connecting portion , and the fastening portion is clamped to the connecting portion in an area adjoining the through opening in which the screw head rests against the fastening portion , wherein the spacer sleeve is held by the screw on the shaft . <EOS>