Why should the crankshaft not be rotated after adding the corrosion preventive mixture into the cylinders of engines prepared for storage?

The correct answer emphasizes the importance of maintaining a proper seal of the corrosion preventive mixture within the engine cylinders. When the crankshaft is rotated after this mixture has been added, it can disrupt the protective layer formed by the mixture on the internal surfaces of the cylinders. This layer is critical for preventing corrosion during the storage period.

By keeping the cylinders sealed, the corrosion preventive mixture can effectively coat the internal surfaces, thereby protecting them from moisture and contaminants that could lead to rust or corrosion over time. Rotating the crankshaft could disturb this seal and allow air and moisture to enter the cylinders, thus negating the protective benefits of the corrosion preventive measures.

Maintaining the integrity of the seal ensures that the mixture remains effective throughout the storage duration, protecting the engine components until it is ready for use again.