Abstract: The invention relates to a process for manufacturing a thermoplastic part (1) with an injected seal (3) as well as to an injection molding apparatus and a corresponding thermoplastic part. For injecting the seal, a groove (2) is formed during molding of the thermoplastic part (1) in which groove liquid crosslinked plastic as material for the seal (3) is injected. Sealing projections (12) are formed on the groove edge and/or on the injection mold in order to prevent an overflowing beyond the groove edges during injection. When closing the mold, undercuts (6) are formed on the upper edge of the groove for holding the solidified seal (3) in the groove.