Why is it important not to rotate the crankshaft after the corrosion preventative mixture has been put into the cylinders on engines prepared for storage?

Why is it important not to rotate the crankshaft after the corrosion preventative mixture has been put into the cylinders on engines prepared for storage?

• A. The piston rings will be damaged
• B. The camshaft timing will be altered
• C. The seal of the corrosion preventative mixture will be broken
• D. Oil seals will leak

Answer: (C)

Corrosion prevention in stored engines relies on a protective film coating the cylinder walls, piston rings, and other exposed metal surfaces to keep out moisture and air. This film forms a seal that stays in place while the engine sits. If you rotate the crankshaft after introducing the corrosion preventive mixture, that protective film is sheared and disturbed. The seal is broken as the coating is smeared or displaced, leaving surfaces exposed and the preservative no longer effective. Once the seal is compromised, rust and corrosion can begin during storage. The other ideas aren’t the main issue here: turning the engine isn’t about damaging piston rings or changing cam timing in storage, and breaking the film seal isn’t primarily what would cause oil seals to leak. Maintaining the integrity of the corrosion-preventive film is the key protection.

Corrosion prevention in stored engines relies on a protective film coating the cylinder walls, piston rings, and other exposed metal surfaces to keep out moisture and air. This film forms a seal that stays in place while the engine sits. If you rotate the crankshaft after introducing the corrosion preventive mixture, that protective film is sheared and disturbed. The seal is broken as the coating is smeared or displaced, leaving surfaces exposed and the preservative no longer effective. Once the seal is compromised, rust and corrosion can begin during storage. The other ideas aren’t the main issue here: turning the engine isn’t about damaging piston rings or changing cam timing in storage, and breaking the film seal isn’t primarily what would cause oil seals to leak. Maintaining the integrity of the corrosion-preventive film is the key protection.