Automotive
As automotive engine oil specifications evolve, older specs can become obsolete either because their performance is no longer needed or for want of test equipment. When market demand remains, the industry looks for workarounds.
The question of when to declare an engine oil specification obsolete is an old one in the lubricant industry, and it raises other questions, too. In many Industries, when something becomes obsolete, manufacturers stop producing it. But that is not what happens with lubricants because engines calling for older quality products remain in use. Industry stakeholders contend with this issue as do all consumers looking for the right lubricant for their engine.
This is a complicated issue with good reasons for specifications to be made obsolete and other compelling reasons to maintain older quality levels. Lubricants have evolved significantly since their inception, but so have fuel, base stock and additive technology. Engine hardware, emissions systems and environmental regulations have also changed and required more exacting lubricants.
In the early 1990s, industry developed formal systems in North America and Europe to defined API and ACEA engine oil specifications, along with rules for running the programs and approving products. Prior to this, I was told as a new formulator, the market resembled the Wild West. OEMs and marketers along with their additive suppliers decided what was acceptable. Base stocks could vary significantly and base oil interchange, viscosity grade read-across and other product development rules did not formally exist. Engine tests did exist, but how they were applied could vary, and most OEMs developed their own genuine oils and approval systems.
The industry had yet to define rules about how many times a test could be run to get a pass or whether passing a test with base stock A could be applied to base stock B. I have heard stories of a Caterpillar 1G2 test being run 30, 40, 50 times until a pass was obtained. This test helped to define a key quality level, API CD, that was claimed on both heavy-duty diesel and gasoline engine oils. This did not mean the oil was bad because claims were based on more than a single test, and marketers and their additive companies applied technical judgement before approving an oil. Today, there are strict rules around engine tests and how they are run. If an oil undergoes a test multiple times it must average a pass or if not a change must be made to improve the oil.
Once upon a time I felt old specifications should become obsolete when replaced by new and better oils that were backwards serviceable. It made good sense in North America, where new higher quality products could easily replace the older quality ones. Still, I did understand why marketers wanted to keep them around, especially in markets that were not geared to a “one size fits all approach,” as we see in North America. Today we will focus on one heavy-duty quality level that was my first as a new formulator: API CF-4, a quality level that is long forgotten in North America but still exists globally. This category has not been specified by an OEM since before the turn of the last century, but there are engines that call for this type of lubricant.
Let’s go back in time to when API CF-4 was introduced. Fuel sulfur levels then could be as high as 5,000 parts per million. Today they are rarely more than 50 ppm anywhere in the world. Heavy-duty lubricants then were made with mostly Group I base stocks, whereas Group II is the most significant base stock component today. The market had SAE 15W-40 multigrades, but about 30% of heavy-duty lubricant sold in the early 1990s were monogrades. Today, monograde oils are almost never seen in North America. We also don’t have the engine tests and fuel that once defined the CF-4 level of performance, nor do we have the old hardware to do proper field testing today, yet CF-4 still exists in some markets.
It begs the question: Can one even formulate for an API CF-4 lubricant today? I truly understand that one can call an oil CF-4, but I contend there is no such thing anymore, and what we have is a repeat of the time before official rules were in place. In such a situation, technical judgement must prevail. But whose technical judgement, and why is the judgement of one marketer or lubricant additive company better or worse than another.
It was an easy call to declare API CF-4 obsolete after environmental regulations drastically reduced fuel sulfur levels, especially for on-road vehicles spurring development of C-series specifications. Off-road vehicles also saw the same trend, and the tests that defined the category became obsolete and could no longer could be supported or run. OEMs did not need or want CF-4, and the new quality levels were all back serviceable, so consumers would not have issue servicing their older engines.
But new oils generally cost more money, so a market remained for older CF-4 oils, and there was significant competitive intensity to define products that were less costly and could still do the job. But how were those decisions made? There were no rules, so marketers and additive companies defined the basis for new products once API CF-4 was declared obsolete and could no longer be licensed.
As a former formulator, I do remember that when CF-4 was the newest category additive treat rates were at least 10% and more like 12%. Total base number of oils was a minimum of 10 and many were 12, 14 or higher. Today I have heard of CF-4 oils with as little as 4.8% additive. Has additive and base stock technology improved so much? Such treat rates bring key zinc dialkyldithiophosphate levels to half of former levels or lower, TBN levels to a fraction of what they were. No, additive and base stock technology have not changed so drastically, but there is no way to recreate CF-4 oils anymore. Marketers can call an oil CF-4, but the tests and fuel that defined CF-4 performance no longer exist.
This is not to say, that all CF-4 oils are bad or won’t work with today’s fuels. One needs less TBN to neutralize acids, these oils are targeted to shorter oil drains, engines are broken in and we know the engine is old, so if it fails can the lubricant really be blamed? I am sure products may also be tested in some vehicles and shown not to harm engines over some limited drain intervals. Still, it’s not the same as doing a field test when an engine is new and running the lubricant for half a million miles with full oil analysis and a mechanical tear-down at the conclusion of the test.
Some products now on the market may have undergone current engine tests set for a certain level of performance — lower than the latest standard. Some may have been formulated using a database of information utilizing past formulation work and additive testing knowledge to estimate what would pass the test today. That said, low additive treat CF-4 oils are more likely than not to only have a fraction of the dispersant seen when the category was not obsolete. If dispersant technology has gotten much better, why are current quality level treat rates so much higher? Additives have improved, but is it realistic to believe additive treats can be reduced by over 50% in some cases?
Short of a mandate or laws that prevent the sale of obsolete products, I believe it may be best if older category specifications can be maintained. This allows a real basis and a true standard developed by industry experts to meet the intent of the original standard and to provide a level playing field. It allows marketers to continue offering a licensed product and to utilize the API donut, which is like the Good Housekeeping seal of approval.
The Category Lubricant Oversight Group has been tasked to maintain these legacy engine oil lubricant categories. Led by Brent Calcut, Afton’s director of the Americas OEM relationship team, CLOG reports to the Lubricant Standards group and consists of industry experts representing all key stakeholders including oil marketers, additive companies, OEMs, test labs and base stock manufacturers. When a performance test is at risk of becoming unavailable, these experts review existing and new tests and perform technical and statistical evaluations to identify a potential replacement. The process can be expensive and can include running current tests on older reference oils to make recommendations to the Lubricants Standards group.
“CLOG is currently tasked with identifying suitable options to replace the Sequence IVA and VIII, which impact many existing categories from API SJ to SN,” he said recently. “When GF-8 test developments are finalized, CLOG may be tasked to propose equivalency limits for the Sequence VJ and VIG tests as well. We expect to have data from the precision matrixes, making the task a bit easier.”
API 1509 Annex A documents how engine oil classifications have evolved and lists those that are now obsolete. According to API, a quality level becomes technically obsolete when original test methods or their alternatives are no longer available to verify performance or when the API Lubricants Committee votes by letter ballot to make a category or categories obsolete. Once a category is declared obsolete, API sets timing for licenses to expire, giving markets time to adjust.
It should be noted that marketers can continue to sell and promote the older products that are formally qualified, but they can no longer license them if the specification is declared obsolete. Over time, old products are usually replaced, and competitive intensity can drive down costs and create new products consistent with any new components and base stocks that become available. Lubricant marketers, with their additive partners using their own methodology and technical expertise, will continue to supply these older products if demand still exists.
A more pressing need may exist for heavy-duty lubricants, where several key tests are no longer supported and will become obsolete, threatening the viability of all existing heavy-duty diesel categories including the current API CK-4 performance standard.
“The Mack T-8 and T-11 and Mack T-12 tests can no longer be maintained and may run out of parts in the next five years,” Calcut said. In the case of the Mack T-8 and 11 tests, the new ISB Viscosity test should be an adequate replacement, and plans are in place to identify equivalency limits. The Mack T-12 is more problematic as no suitable replacement test has yet been identified. Industry stakeholders determined during PC-12 development that other industry wear tests provided sufficient wear protection, and the Mack T-12 was redundant. In this case, identifying a suitable replacement test for existing API categories is much more challenging.
From my view the effort to maintain older heavy-duty diesel classifications such as API CH-4 and CI-4, which represent the majority of diesel engine oil sold around the world today, is an industry imperative. It is critical for oil marketers to be able to provide these products given that there are many engines that are 15-20 years old or older. Newer quality lubricants are not even needed in many developing countries.
Oil marketers I have spoken to seem to strongly prefer having older oil quality standards maintained to ensure a level playfield and to give end users a reason to trust that product integrity is being maintained and potentially still licensed. It gives consumers the option to buy a more competitive oil rather than stepping up to a newer level. So, as much as I would like to get rid of older qualities as many OEMs do, I believe it is important to maintain older specifications if local laws do not prevent their use. Some countries relatively recently set the minimum oil quality at CH-4, which really helps to remove the lowest quality oils from the market and should be seen as good news. It also makes it difficult to eliminate CH-4 soon after.
As for CLOG, it’s an under-appreciated team effort that is critical to ensure the validity of engine oil quality for older engines. This job will become more complicated in the future since many new oils and lower viscosity grades are not backwards compatible or just may not be preferred by some OEMs, causing even more fragmentation or potential for misapplication. I am quite confident that global and regional marketers will ensure the right products are available for both new and older oil engine applications for as long as the demand exists. 
Steve Haffner is president of SGH Consulting LLC. He has over 40 years of experience in the chemical industry, priamarily with Exxon Chemicals Paramins and Infineum USA. Contact him at sghaffn2015@gmail.com or 908-672-8012.