Engine assemblies of automotive combustion engines such as the cylinder head, control housing, cylinder head hood and oil pan are usually preassembled and tested before they are delivered as an assembly to the engine main assembly line. Usually, these pre-assembly lines are placed directly in the engine assembly as a supplementary side line. Increasingly, pre-assembly is also being shifted to subcontractors such as foundries and plastics processing companies. Oil pans, for example, are then poured, processed and pre-assembled by the supplier. Integrated manufacturing systems of the material flow between machine tools are not assigned here. Typical mounted components are sensors such as oil level sensors and rotary encoders, seals such as shaft seals and O-rings, locking elements and oil filler necks. Subsequently, a leak test is carried out with many assemblies.