Bearing Running Hot

The Shepherd Manuals Bearing Running Hot — Industrial Troubleshooting Field Guide is a focused field reference for industrial mechanics, millwrights, maintenance technicians, reliability technicians, apprentices, and instructors who need to quickly determine why a bearing is overheating.

This guide is built around a real maintenance problem:

“The bearing is running hot. What is causing it?”

Instead of replacing the bearing and hoping the problem goes away, this guide helps the technician work through the actual causes step by step.

Topics Include

• What “running hot” really means
• Normal temperature versus abnormal temperature trend
• Over-lubrication
• Under-lubrication
• Incorrect lubricant
• Mixed or contaminated grease
• Blocked grease relief paths
• Excessive belt tension
• Excessive chain loading
• Misalignment
• Soft foot
• Incorrect shaft or housing fit
• Loss of internal bearing clearance
• Improper bearing installation
• Excessive preload
• Seal drag
• Contamination
• Mechanical overload
• Shock loading
• Internal bearing damage
• Raceway and rolling-element damage
• Cage problems
• Spalling
• False brinelling
• Electrical fluting where applicable
• Temperature measurement techniques
• Infrared thermometer use
• Thermography considerations
• Using vibration and noise to support the diagnosis

Troubleshooting by Symptom

The guide also helps diagnose conditions such as:

• Bearing hot immediately after greasing
• Bearing hot after replacement
• Bearing temperature gradually increasing
• Bearing suddenly running hotter than normal
• Bearing hot only under full load
• Bearing hot and noisy
• Bearing hot with high vibration
• One bearing hotter than the opposite bearing
• Motor drive-end bearing running hot

Full-Page Troubleshooting Flowchart

A large troubleshooting flowchart guides the technician through:

TEMPERATURE ABNORMAL → LUBRICATION → LOAD → ALIGNMENT → SEALS → FIT/CLEARANCE → VIBRATION/NOISE → INTERNAL DAMAGE

The objective is to locate the true cause before replacing components unnecessarily.

Practical Field Reference

Also included:

• Hot-bearing symptom/cause table
• First-check recommendations
• Field inspection checklist
• Temperature and condition recording
• Real-world troubleshooting examples
• Corrective-action guidance

This guide is designed for the plant floor, maintenance shop, technical classroom, or reliability program.