On the Cusp of Change: SN+, 0W-16, GF-6 and More

The current status of motor oils in the U.S. market is getting confusing. Let’s see if we can sort it all out and give you the background you need to provide your customers with the service they need.

Current Specs & Backward Compatibility

The American Petroleum Institute (API) sets standards for engine oils. These standards are designed to protect the engines in cars and trucks. Currently, the API category recommended for cars and light trucks is API SN. Because of the way the API categories are developed, the most recent category is compatible with older engines. This is known as backward compatibility. However, there are some classic car enthusiasts who have either had or have heard of problems with wear in flat tappet engines. These engines are pre-1990 designs and seem to have a need for higher phosphorus levels in the engine oil. Since phosphorus is related to zinc content, they may refer to oils as high-zinc or low-zinc.

Starting with API SH, phosphorus levels were set at 0.12-percent max, which was not a problem for flat tappet engines. API SJ reduced the phosphorus to 0.10-percent max. API SL stayed at 0.10-percent max phosphorus. API SM and SN dropped to the current level of 0.08-percent max phosphorus. (Note: Your customer who has that classic muscle car will want to have enough phosphorus in his oil to protect the valve train. In that case, the best choice for him is API CJ-4 Heavy Duty Diesel engine oil as either an SAE 10W-30 or SAE 15W-40.)

Generally speaking, API SN is the current recommendation for engine oil. If the oil includes energy conserving properties, it is called SN-Resource Conserving (SN-RC). However, the more familiar identification is API GF-5. The GF series of engine oils is the result of the automobile manufacturers requiring a single designation for specific viscosities and fuel economy benefits. API and the OEMs worked together to come up with a system that allows the oil buying consumer to select an oil meeting the needs of their vehicle. Since the GF series is the current API S category plus a fuel economy test, buying a GF oil will ensure the same backward compatibility needed for older engines.

Introduction of SN+

Things have changed, however. In a recent press release from Phillips 66, Mike Krampf, Phillips 66 Finished Lube manager, noted that OEMs have developed and introduced new engine designs, such as gasoline direct injection (GDI) and its turbocharged brother (TGDI). These are small and more powerful engines, but they also run hotter. The high pressures from turbocharging combined with direct fuel injection in these smaller TGDI engines make them susceptible to a condition called low speed pre-ignition, or LSPI.

Krampf noted that more than 120 million turbocharged GDI-powered vehicles have been manufactured since 2010 and are at risk for LSPI. Since GDI engines now make up over half of new car production, it has become necessary to develop new oil formulations to counter this problem. API has been working with OEMs, oil marketers and additive suppliers to find a solution to the problem — API SN Plus (SN+).

In a letter to the oil and auto industries, API’s Kevin Ferrick announced that on November 9, 2017, the API Lubricants Standards Group approved the adoption of SN+, a new classification that may be used in conjunction with API SN and API SN-RC.

The letter continued that API plans to license oils against the SN+ classification, but the date on which SN+ licensed oils will appear in the API Directory of Licensees and Licensed Marketers still needs to be determined. That will depend on when the Base Oil Interchange and Viscosity Grade Read Across guidelines are completed and reviewed. The API “donut” for the new products will look like this:

Preliminary data shows that additives affect oil performance much more than base stock selection or other factors. This should allow for generous base oil interchange and the deployment of the new category in the base stocks that oil marketers need covered. As of press time, the best estimates for first licensing date of SN+ are May 1, 2018. At that time, you can expect to see announcements from all major oil marketers about SN+.

The bottom line is that SN+ and SN+ Resource Conserving will be the proper oil for your operation and will continue to be labeled GF-5 according to viscosity grade. Remember the only SAE grades covered by GF-5 are SAE 0W-XX, SAE 5W-XX and SAE 10W-30.

Progress of 0W-16 and GF-6

The variety of viscosity grades available includes some new faces: namely SAE 0W-16 and SAE 5W-16. Both of these grades are being introduced to help improve fuel economy. No North American oil marketer currently is offering these grades, but provision has been made for them in the API SN and SN-RC requirements. Honda has started to specify the use of SAE 0W-16 engine oil, which is currently available at Honda dealers.

API GF-6 development, which was started in 2012, still has not been approved. When the program started, everyone assumed it would be in place by sometime in 2016. However, with revisions to three existing tests and the addition of seven new tests, the project got very complex. Add to it the development and introduction of CK-4/FA-4, and it soon became apparent that 2016 was out of the question. Since then, the timing keeps slipping as delays in test revisions and development have not been straightforward. In fact, the SN+ category was introduced at the insistence of the OEMs because of the delays in GF-6.

Currently, the Sequence IVB test, which measures valve train wear protection, is still not ready for prime time. The test has been unable to satisfactorily discriminate between good and failing oils. There was some hope from the December meeting of the API Auto Oil Advisory Panel that the Sequence IVB would be ready to go, but it still is having trouble.

Everyone involved with the GF-6 development program is reluctant to project an introduction date. Had the Sequence IVB development been successful, the target date for introduction was the first quarter of 2020. No such luck, and now, more concerns. It’s reasonable to assume that GF-6 will appear in 2020, but whether it’s early in the year or late is anybody’s guess.

These new category developments are very laborious and expensive. CK-4 is estimated to have cost in excess of $350 million to develop. Whereas, a test program for oil marketers to prove that an oil meets the criteria for a new category costs $1 million or more!

In an effort to reduce costs, the industry has developed a procedure that recognizes that some base oils are more difficult than others. The same goes for viscosity grades. The methodology is to take the worst base oil combinations in the toughest viscosity grades, pass the tests there and allow that result to cover other base oils and viscosities. It works, but takes a lot of time and effort to develop the supporting data. Once all of that is done, the category development process allows oil marketers time to develop their product lines. You can see from all the steps, it takes a lot of time even when there are no hiccups in test development.

So, we have API SN+ on the cusp. We have GF-6 still undecided and at least two years away, and we have SAE XW-16 not yet in the marketplace — but will be soon. There’s a lot of activity in new viscosities and specifications, and no signs of slowing down.

Steve Swedberg

STEVE SWEDBERG has over 50 years of experience in the oil industry. He has a Bachelor of Science degree in chemistry and graduate work in business administration. He also has extensive training in petroleum products technical service as well as total quality management. His work experience includes lubricants research and development with ARCO and UNOCAL, oil additive marketing at Edwin Cooper (now Afton) and Chevron Oronite and lubricants marketing with Pennzoil. He managed technical groups related to oil marketing, product quality and technical services. Swedberg has also been involved with several industry organizations including STLE, NLGI, ASTM and, most notably, SAE, where he was Technical Committee 1 (Engine Oils) chairman from 1992 to 1996. While in that position, he was able to help influence industry direction as well as make many valuable industry contacts. Swedberg is currently consulting on lubricating products and additives and is a technical writer.