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Oil Seal Failure Checklist: Symptoms, Causes, and Recommended Actions

Oil Seal Failure Checklist: Symptoms, Causes, and Recommended Actions


Oil seals, also known as rotary shaft seals, play a crucial role in preventing the leakage of fluids, such as oil, from machinery or equipment. However, there are various factors that can contribute to oil seal failures, leading to leaks and potential damage.

This guide aims to provide an overview of common reasons why oil seals may fail and provides recommendations for addressing these issues.

There are two parts an Oil Seal / Rotary Shaft Seal where leakage can occur:

  • The interface between housing bore and seal O.D
  • Between the seal lip and shaft

Oil Seal Failure Checklist

Oil Seal rotates with shaftSeal O.D smaller than bore I.DSelect correct size seal and replace
Oil Seal moves in axial direction along shaftSeal O.D smaller than bore I.D and caused by the rotating of shaft or the internal pressureSelect correct size seal and replace
Seal installed in declining conditionThe I.D of housing bore is undersized, incorrect means of installation causing the seal to be misalignedEnsure housing bore is correct size
Deformation of the metal caseUse of incorrect installation toolUse correct installation tool
Damage on the case O.DThe finish of housing is not correct and / or incorrect means of installation Dirt adhering to the seal O.D or the housing I.DEnsure housing size is correct
Use correct installation tool
Lip worn seriouslyInsufficient lubrication
Application design restricts lubricant
access to seal lip
Ensure sufficient lubricant
Change design to ensure seal lip is accessible to lubricant
Lip worn seriouslyInner pressure too highChange seal design to pressure type
Lip partially wornSeal partially installed
T.I.R of I.D and O.D are too big
Select seal with suitable T.I.R (Total Indicated Runout)
Lip partially wornSeal misaligned in housingEnsure housing bore is correct
Use correct installation tool
Lip hardened, worn, and crackedHigh temperature, shaft rotation speed, or pressureSelect suitable compound type
Supply sufficient lubricant
Lip material swollenIncorrect compound selectionSelect the correct compound
Lip scratchedShaft surface not smooth
Scratch caused by incorrect installation tool
Let all the lip configuration clear
Install seal correctly
Lip turning outIncorrect installation
Inner pressure too high
Lubricate the lip and shaft before installation
Use pressure type seal
Crack on the base of flex sectionInner pressure too high
Sudden pressure strike on the flex section
Use high-pressure type seals
Spring dislodged from spring grooveShaft chamfer is incorrect
Incorrect installation
The retainer lip is too short
Finish the shaft chamfer and lubricate before installation
Be careful while installing
Change the seal design


Understanding the potential reasons for oil seal failures is essential for maintaining the proper functioning of machinery and preventing leaks. By recognizing the symptoms, identifying the causes, and implementing the recommended actions outlined in the checklist, you can address oil seal issues effectively.

Regular inspection, proper installation techniques, and selecting the correct seal size and compound for the operating conditions are crucial steps in preventing oil seal failures.

Additionally, ensuring sufficient lubrication and addressing issues related to pressure, alignment, and surface conditions can significantly contribute to the longevity and effectiveness of oil seals.

By following this checklist and taking proactive measures, you can minimize the risk of oil seal failures, enhance the performance of your equipment, and avoid potential downtime and costly repairs associated with oil leaks.

Discover More:

Understanding Oil Grades: A Comprehensive Explanation
Understanding the API Index of Engine Oil

6 Myths About Engine Oil

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