MDE Unit 16 Q2 – Answer

Diesel Engine High Bearing Temperatures: Causes and Procedures

High bearing temperatures in a diesel engine can be a serious issue and should be addressed promptly. Here’s a breakdown of the possible causes and the recommended procedure upon detection:

(a) Possible Causes of High Bearing Temperatures:

  • Insufficient Lubrication:
    • Low Oil Level: Insufficient oil in the crankcase reduces oil’s ability to absorb heat and lubricate bearings effectively.
    • Worn Oil Pump: A worn pump may not deliver enough oil pressure to reach all bearings properly.
    • Clogged Oil Filter: A blocked filter restricts oil flow, leading to inadequate lubrication and increased bearing temperatures.
  • Bearing Wear: Worn bearings can increase friction and reduce oil clearance, leading to higher bearing temperatures.
  • Excessive Engine Load: Operating the engine under heavy load for extended periods can generate excessive heat, straining the lubrication system and raising bearing temperatures.
  • Coolant System Issues: Overheating, due to a malfunctioning cooling system, can indirectly increase bearing temperatures as overall engine heat rises.
  • Contaminated Oil: Dirty oil with debris or excessive air bubbles can hinder heat transfer and lubrication, leading to higher bearing temperatures.

(b) Procedure Upon Detection of High Bearing Temperatures:

  1. Immediate Shutdown: Safely reduce engine load and stop the engine as soon as possible. Continued operation with high bearing temperatures can lead to bearing failure and catastrophic engine damage.
  2. Identify the Cause: Investigate the reason behind the high temperature. Check oil level, oil pressure, and coolant system functionality. Look for signs of bearing wear or oil leaks.
  3. Monitor Engine Temperature: Continuously monitor engine temperature even after shutdown as hot components can cool down slowly.
  4. Do Not Restart: Avoid restarting the engine until the cause of the high temperature is identified and addressed.
  5. Consult a Mechanic: Depending on the severity of the issue, professional help from a qualified mechanic is highly recommended. They can diagnose the problem, perform necessary repairs (such as replacing worn bearings or oil pump), and ensure safe engine operation.

Additional Tips:

  • Maintain a regular oil change schedule with the recommended oil grade for your engine.
  • Monitor engine gauges regularly, paying attention to oil pressure and temperature readings.
  • Address any minor oil leaks promptly to prevent oil loss and potential lubrication issues.
  • Avoid overloading the engine for extended periods.

By following these steps and taking preventative measures, you can help minimize the risk of high bearing temperatures and ensure the longevity of your diesel engine.