What is the primary function of filters in the lubrication system?

• A. Remove foreign particles in oil.
• B. Increase oil viscosity.
• C. Cool oil.
• D. Add fuel to oil.

Answer: (A)

The main job of filters in the lubrication system is to remove foreign particles from the oil, keeping the lubricant clean and protecting moving parts from wear, scoring, and clogged passages. When dirt, metal shavings, and other contaminants are filtered out, oil can flow freely through ducts and bearings, maintaining proper lubrication and extending component life, especially during startup and under heavy operation.

Filters don’t change the oil’s viscosity—that’s set by the oil grade and temperature. They also don’t cool the oil; cooling is done by an oil cooler or heat exchanger. And they don’t add fuel to the oil—fuel contamination is something to avoid, and filtration aims to prevent it.