You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass

    Change of High-Shear-Rate Viscosity of Engine Oils During Use: A Review

    Published: 01 January 1989

      Format Pages Price  
    PDF (240K) 14 $25   ADD TO CART
    Complete Source PDF (2.0M) 109 $55   ADD TO CART

    Cite this document

    X Add email address send
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    It has long been known that the kinematic viscosities of multigrade engine oils change with use, the typical pattern being an initial decrease followed by a gradual increase. Recent work has shown that the patterns of change of the high-temperature, high-shear (HTHS) viscosity are different than those of the kinematic viscosity. These results, coupled with recent bearing oil film thickness results, suggest that kinematic viscosity changes are less significant in the operation of the bearings of engines than has been assumed. The pattern of HTHS viscosity change has been found to depend on both viscosity index (VI) improver type and engine test. Oil-thickening effects tend to be more prominent in the HTHS viscosity patterns than in the kinematic viscosity patterns.


    engine oils, polymers, shear stability, shearing, VI improvers, viscometer, viscosity

    Author Information:

    Alexander, DL
    Technologist, Texaco Research Center, Beacon, NY

    Committee/Subcommittee: D02.07

    DOI: 10.1520/STP23003S