ASTM D7097 - 16a

    Standard Test Method for Determination of Moderately High Temperature Piston Deposits by Thermo-Oxidation Engine Oil Simulation Test—TEOST MHT

    Active Standard ASTM D7097 | Developed by Subcommittee: D02.09.0G

    Book of Standards Volume: 05.04


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    Significance and Use

    5.1 The test method is designed to predict the deposit-forming tendencies of engine oil in the piston ring belt and upper piston crown area. Correlation has been shown between the TEOST MHT procedure and the TU3MH Peugeot engine test in deposit formation. Such deposits formed in the ring-belt area of a reciprocating engine piston can cause problems with engine operation and longevity. It is one of the required test methods in Specification D4485 to define API Category-Identified engine oils.6

    1. Scope

    1.1 This test method covers the procedure to determine the mass of deposit formed on a specially constructed test rod exposed to repetitive passage of 8.5 g of engine oil over the rod in a thin film under oxidative and catalytic conditions at 285 °C. The range of applicability of the Moderately High Temperature Thermo-Oxidation Engine Test (TEOST MHT2) test method as derived from an interlaboratory study is approximately 10 mg to 100 mg. However, experience indicates that deposit values from 1 mg to 150 mg or greater may be obtained.

    1.2 This test method uses a patented instrument, method and patented, numbered, and registered depositor rods traceable to the manufacturer3 and made specifically for the practice and precision of the test method.4

    1.3 The values stated in SI units are to be regarded as standard.

    1.3.1 Although not an SI unit, the special name liter (L) is allowed by SI for the cubic decimeter (dm3) and the milliliter (mL) for the SI cubic centimeter (cm3). Likewise, the special name millimeter (mm) is allowed by SI as a measurement of length.

    1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D4485 Specification for Performance of Active API Service Category Engine Oils

    D6335 Test Method for Determination of High Temperature Deposits by Thermo-Oxidation Engine Oil Simulation Test


    ICS Code

    ICS Number Code 75.100 (Lubricants, industrial oils and related products)

    UNSPSC Code

    UNSPSC Code 15121501(Engine oil)


    Referencing This Standard
    Link Here
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    DOI: 10.1520/D7097-16A

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    Citation Format

    ASTM D7097-16a, Standard Test Method for Determination of Moderately High Temperature Piston Deposits by Thermo-Oxidation Engine Oil Simulation Test—TEOST MHT, ASTM International, West Conshohocken, PA, 2016, www.astm.org

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