Specifications for a new viscosity grade, SAE 16, will be published in a revision to “SAE J300: Engine Oil Viscosity Classification” on April 2, 2013.
The J300 revision was requested by a consortium of passenger car OEMs to provide a viscosity grade lower than SAE 20.
“The main driving force for using lower-viscosity oils is to lower hydrodynamic friction, thereby increasing fuel economy,” said Michael Covitch of Lubrizol, Chair of the SAE International Engine Oil Viscosity Classification (EOVC) task force.
He explained the new grade will be specified in the future by OEMs for cars specifically designed to use new low-viscosity oils. It is not deemed to be suitable for use with older engines or newer vehicles not designed for such low-viscosity oils. Covitch noted that the numeral in SAE 16 “has no inherent meaning” and is used only for the purpose of categorization."
SAE J300 is used worldwide to classify engine oils in terms of viscosity grade. OEMs recommend specific viscosity grades in owner manuals to ensure that their engines will perform throughout the lifetime of the vehicle. Most engine oil standards set by organizations such as the American Petroleum Institute and individual OEMs include requirements for oils to meet the limits found in J300.
Covitch told AEI that the EOVC task force (a standing committee of SAE Technical Committee 1) “debated long and hard on what to call the new high-temperature viscosity grade.” Currently, the lowest high-temperature grade is SAE 20. It wasn’t a simple matter of following convention and using the next-lowest multiple of 5 for two reasons. First, J300 addresses both high- and low-temperature grades (the latter use “W” to indicate “winter”).
“The most compelling reason is that one of the most popular SAE viscosity grades for heavy-duty diesel trucks around the world and diesel passenger cars in Europe is SAE 15W-40,” Covitch said. “Our task force was concerned that adopting SAE 15 might be confusing to consumers familiar with SAE 15W-40 oils and might lead to misapplication of the wrong oil in the wrong vehicle, particularly vehicles not designed to operate on such low-viscosity lubricants."
The second incentive to adopt SAE 16 was in anticipation of new lower engine oil viscosity grades that could be defined in future revisions of J300.
"If we continued to count down from SAE 20 to 15 to 10, etc., we would be facing continuing customer confusion issues with popular low-temperature viscosity grades such as SAE 10W, SAE 5W, and SAE 0W," he noted. "By choosing to call the new viscosity grade SAE 16, we established a precedent for future grades, counting down by fours instead of fives: SAE 12, SAE 8, SAE 4."
Covitch said the EOVC task force recognized that using the unfamiliar "SAE 16" name might make consumers think twice before selecting the right oil for his/her vehicle.
Besides adding the SAE 16 grade, the new revision to J300 also revises the minimum high-temperature viscosity range of SAE 20. “In the past, an SAE 20 oil’s kinematic viscosity, measured at 100°C (212°F) was 5.6 cSt (centistokes) to less than 9.3 cSt," Covitch explained. "This was a much broader range than SAE 30, 40, 50, or 60, and the lower part of the old SAE 20 range was not being utilized. Therefore, the minimum kinematic viscosity was increased to 6.9 cSt to bring the range of SAE 20 in line with that of the higher-viscosity grades.”
The new standard was officially approved by SAE Fuels & Lubricants Council in Norfolk, VA, in December 2012. Publication was delayed for a few months to give other lubricant standards organizations affected by the revision time to make any changes necessary to be in full compliance before publication of the new J300 document.
J300 currently addresses high-temperature grades (SAE 20, 30, 40, 50, and 60) and low-temperature grades (0W, 5W, 10W, 15W, 20W, and 25W). In general, Covitch said, the higher numbers indicate higher-viscosity oils designed for vehicles operating in high-temperature environments or for vehicles requiring high-viscosity oils for maximum wear/durability protection. Lower numbers indicate lower-viscosity oils which are recommended for vehicles operating in cold climates and/or for engines designed for maximum fuel economy.
The new J300 revision does not make any changes to the low-temperature W grades.