5.1 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.

5.2 The increase in oil viscosity obtained in this test method 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.

5.3 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.

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

5.5 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 method.

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

5.6.1 Specification D4485,

5.6.2 Military Specification MIL-PRF-2104, and

5.6.3 SAE Classification J183.