A holding dowel (10) for fastening a fastening means to a component (22), in particular to a vehicle body part, is adapted to be inserted into and arrested in an opening (20) of the component (22) and has a mount (26) for the fastening means. The holding dowel (10) has a base body (12) made from a hard material, which protrudes into the opening (20) and is adapted to fix the holding dowel (10) in place in the opening (20), and further has a sealing member (18) made from a flexible plastic material, which includes a surrounding sealing lip (38). In the installed condition of the holding dowel (10), the sealing lip (38) rests against the component (22) and seals the opening (20) of the component (22). The sealing member (18) is produced at least partly from a material which under the influence of heat establishes a substance-to-substance bond with the component (22).