This test method was developed to evaluate automotive engine oils for protection against oil thickening and engine wear during moderately high-speed, high-temperature service.

The increase in oil viscosity obtained in this test indicates the tendency of an oil to thicken because of oxidation. In automotive service, such thickening can cause oil pump starvation and resultant catastrophic engine failures.

The deposit ratings for an oil indicate the tendency for the formation of deposits throughout the engine, including those that can cause sticking of the piston rings in their grooves. This can be involved in the loss of compression pressures in the engine.

The camshaft and lifter wear values obtained in this test provide a measure of the anti-wear quality of an oil under conditions of high unit pressure mechanical contact.

The test method was developed to correlate with oils of known good and poor protection against oil thickening and engine wear. Specially formulated oils that produce less than desirable results with unleaded fuels were also used during the development of this test.

The Sequence IIIG engine oil test has replaced the Sequence IIIF test and can be used in specifications and classifications of engine lubricating oils, such as the following:

1.1 This test method covers an engine test procedure for evaluating automotive engine oils for certain high-temperature performance characteristics, including oil thickening, varnish deposition, oil consumption, as well as engine wear. Such oils include both single viscosity grade and multiviscosity grade oils that are used in both spark-ignition, gasoline-fueled engines, as well as in diesel engines.

1.1.1 Additionally, with nonmandatory supplemental requirements, a IIIGA Test (Mini Rotary Viscometer and Cold Cranking Simulator measurements), a IIIGVS Test (EOT viscosity increase measurement), or a IIIGB Test (phosphorous retention measurement) can be conducted. These supplemental test procedures are contained in Appendixes Appendix X1, Appendix X2, and Appendix X3, respectively.

Note 1—Companion test methods used to evaluate engine oil performance for specification requirements are discussed in SAE J304.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.2.1 Exception—Where there is no direct SI equivalent such as screw threads, national pipe threads/diameters, and tubing size.

1.3 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. Specific warning statements are provided in 6.14.1.1 and 7.1.