Today, technological plugs designed to protect the internal cavities of parts and assembly units are manufactured using such production methods as casting or stamping. At the same time, their subsequent processing is a time-consuming process. Additive technologies can save material, save time and reduce expenses. This study considers the possibility of manufacturing technological plugs for engine box and oil system using additive technologies. The cover plugs were printed using the Fusion Deposition Modeling (FDM) method on a Russian-made ZENIT printer. PLA plastic was chosen for 3D printing. The plug models were optimised, which allowed correcting and reducing the estimated printing time. In particular, some plugs were made assemblable, which helped to avoid a large number of printing supports. The production of technological plugs using additive technology allows reducing the cost of the finished product, the weight of the plugs and the estimated time of their production.