The preservation of antique vehicles represents a great challenge, an intersection of multiple disciplines among cultural heritage and mechanical engineering. This thesis focuses on the reproduction of the steam-water injector, representing probably one of the earliest implementations of this device in a road vehicle. Additive Manufacturing (AM) was selected as the suitable fabrication method, owing to its ability of realizing intricate internal geometric features and its advantage of avoiding the need of additional tools. The injector was redesigned considering Design for Additive Manufacturing (DfAM) principles, taking into account both the possible advantages and the intrinsic limitations of the AM processes. This work demonstrates the capabilities of the integration of RE and AM techniques in the reconstruction of complex historical devices, providing a replicable framework for future adoptions in the field of industrial heritage conservation and restoration..