Why is it inadvisable to soak aluminum and magnesium engine parts in soap solutions?

Soaking aluminum and magnesium engine parts in soap solutions is inadvisable due to the potential for contamination and foaming of the engine oil. Soap solutions can leave residues that may interact with the lubricants in the engine, leading to changes in oil properties or causing the oil to foam. Foaming can hinder the oil's ability to lubricate effectively, leading to increased wear and potential failure of engine components. Effective lubrication is crucial for the performance and longevity of engine parts, especially in high-stress environments.

It’s essential to keep sensitive engine components clean yet free from substances that can interfere with their operation. Therefore, when cleaning aluminum and magnesium parts, methods that do not introduce soap residue are preferred to maintain proper lubrication and engine function.