What is a primary indicator of main bearings distress in an engine?

High oil temperatures serve as a primary indicator of main bearings distress in an engine because they reflect the operating conditions and health of the lubrication system. When main bearings experience distress or increased wear, it often results in higher friction and heat generation. Elevated oil temperatures suggest that the lubricant is struggling to reduce friction adequately, which can be due to insufficient oil flow, poor oil quality, or the bearings themselves starting to fail.

Monitoring oil temperatures is crucial, as consistent high temperatures can lead to serious engine damage if not addressed promptly. It indicates that the bearings may not be functioning correctly, potentially leading to premature wear or failure. Therefore, keeping an eye on oil temperatures is critical for ensuring the longevity and reliability of the engine's performance.