FAA Powerplant Written Practice Test

What is the effect of moisture in the lubricating oil over time?

1. It enhances the lubricating properties

2. It leads to oil degradation

3. It increases oil viscosity

4. It has no significant effect

The correct answer is: It leads to oil degradation

Moisture in lubricating oil can significantly impact its performance and longevity. Over time, the presence of water can lead to oil degradation, which occurs through various mechanisms such as hydrolysis, the breakdown of oil additives, and the formation of sludge and acids. This degradation reduces the oil's ability to lubricate effectively, as it alters its chemical properties and can result in the formation of harmful by-products. The accumulation of moisture also encourages oxidation, which can lead to the formation of varnish or sludge that further impairs the oil's function. Additionally, corrosion can occur in engine components due to the presence of water, which can lead to further breakdown of the lubricating properties. Therefore, understanding the adverse effects of moisture in lubricating oil is crucial for maintaining the longevity and efficiency of an engine.