Automotive Lubricants



When I went off to college, I was undecided as to whether I would major in chemistry or physics. Both subjects fascinated me, and on top of that, science was the subject to be taking. To date myself, that was just a few years after Sputnik, and the United States was in a science frenzy and locked in the space race against the Russians. Today we are talking STEM (science, technology, engineering and mathematics), essentially the same thing.

I soon decided that chemistry was my preference, since physics had so much advanced math that I wasnt interested in doing. After my first two years of basic chemistry, I started getting into upper class subjects, including physical chemistry, affectionately known as PChem. Id been warned by others that PChem was a real shock to the system, and they were right.

The first thing we studied was the relationship between physics and chemistry with all that advanced math! I was trapped. Those studies involved a lot of thermo­dynamics, which is where I first met entropy. I wont bother you with the technicalities, but suffice to say that entropy represents the degree of disorder or randomness in a closed system. I think that the automotive oil industry is becoming a marketplace where entropy is growing.

As I like to do, I want to go back to the roots of the automotive industry, especially the engine oils, to get a grip on whats happening. At the dawn of the auto age, non-additive, petroleum based engine oils were in use. These remained the choice of engine manufacturers into the 1930s.

As engine design developed, higher loads were placed on the various internal systems. Horsepower was raised and with it problems from deposits and wear. Additives such as antifoam and pour point depressants, followed by detergent and antiwear agents, came into common use, especially during World War II.

Soon automakers were in a horsepower race for the biggest and most powerful engines, and with that, the automobile grew to monstrous size. Anyone remember the great land barges of the 50s and 60s? This was the era of 409 cubic inch and larger engines delivering the power needed to move those several-thousand-pound beasts. Original equipment manufacturers responded with oil specifications for their particular engine needs.

Then along came smog. The identification of air pollution and the subsequent introduction of emissions controls led to big changes in engine design. One obvious way to reduce emissions was to reduce fuel consumption, so fuel economy became a target. A 27.5 mile-per-gallon minimum for the average of all cars made by any OEM was introduced in 1975, with full implementation a decade later. V8 engines became smaller and V6 engines became much more popular. Improvements in combustion and the introduction of fuel injection, which included an onboard computer, improved both emissions and miles per gallon. At the same time, vehicle weight was reduced to improve emissions and fuel economy.

The oil industry was busy, as well. The earliest oil specifications were OEM specific. That was difficult in terms of inventories, as most oil changes were do-it-yourself. That meant a lot of different brands and labels to work with. The American Petroleum Institute worked out a pretty definitive system (API Service Categories), which set general product quality standards. The OEMs were okay with that, but always had some concerns about what these oils could do and whether they had to work with oils that didnt have all of the bells and whistles they wanted.

There was an agreement reached after a lot of discussion, which gave the OEMs more assurances. Primarily, the ILSAC GF standards added fuel economy to specific viscosity grades and made it easier for the consumer to identify products suitable for their cars and light trucks. API managed the system and set it up so API categories, plus fuel economy, defined the GF series.

Two newer impacts on the market are new viscosity grades and different base stocks. For many years, SAE 5W-30 has been the standard viscosity grade for gasoline fueled engines. After some early caution about the thinner grade versus the traditional SAE 10W-30 and SAE 10W-40, SAE 5W-30 has been the most recommended viscosity. Things are changing with the advent of SAE 5W-20 and SAE 0W-20. Lower viscosity is the easiest way to achieve improvements in fuel economy and emissions.

The Japanese have taken it even further. First, Honda began recommending SAE 0W-16 in 2016. This grade was so radical that SAEs Engine Oil Viscosity Classification Taskforce added not only SAE 16 to the list of viscosity grades, but also included SAE 12 and SAE 8. There is a current effort underway in Japan to develop and market an SAE 0W-8 engine oil. This grade will certainly capture as much fuel economy as anyone is willing to go for at this time. However, there are discussions about potentially lower viscosities to come.

Base oils come into play with the new order. As the performance of engine oils has become more robust, the quality of base oils has improved. Its not to say that the base stocks of 50 years ago were of poor quality; the fact is that oxidation, deposit formation, viscometrics (especially low temperature) and volatility have become more important.

New refining techniques have improved not only yields but the quality of base stocks. Lower viscosities are stable and have low volatility. Low temperature performance has improved as new pour point depressants have been introduced. Viscosity index is higher and heteroatoms are virtually eliminated. There is also a growing list of synthetics (not including API Group III oils) that are finding their way into engine oils because of their superior stability and low volatility, even at a higher cost.

Additive chemistry has also become part of the story. Because of the impact of certain additive components on catalytic emissions controls, vital antiwear and detergent products have been minimized or removed. While substitute materials have been found, there are still concerns about future impacts, and the search for new materials continues.

Thats where we are now in North America, including the Japanese OEMs. Meanwhile, the European Automobile Manufacturers Association has its own set of standards referred to as the ACEA Oil Sequences. In some ways they mirror the API system, but have seemingly many more categories currently active. In addition, European OEMs include brand-specific tests for their vehicles, which makes things more confusing.

To date, the Europeans havent demanded ACEA oils for their vehicles. On the other hand, Japanese OEMs prefer genuine oils in their market. These oils are not developed according to any general standard but are really OEM specific. General Motors has its own oil specification, Dexos, which is a worldwide standard for its vehicles. It is designed to be readily available to supply the same oil globally.

For many years, we have been able to maintain one system and one set of tests to cover North America and imports. However, with the advent of turbocharged gasoline direct injection engines, new classes of hybrids, different viscosity grades, additional tests from ACEA, OEMs and the overall complexity of the entire system, we are finding it almost impossible to improve oils in a timely manner.

By the time ILSAC GF-6 reaches its targeted introduction in 2020, it will have taken eight years to be completed. In the meantime, new engine developments may make GF-6 insufficient for the latest engine designs. Whats more, OEMs and European standards may have moved further ahead in creating another category development. If were lucky, we can take an API SN-Plus approach and add or update a test to capture a quantitative measurement of the needed improvements.

Heres where I think entropy is taking its toll. More chaos has been introduced by the proliferation of tests, categories, engine designs and engine oil formulations. What was once orderly and logical has become fragmented and seemingly resistant to coordination. Too much is being demanded of tests that are, at best, a single engine run in a specific cycle with limited correlation to the field. In point of fact, even though North America has been using E10 gasoline (fuel with 10 percent ethanol) for a number of years, none of the current or proposed engine tests use E10 fuel.

Base stocks have changed over time and will continue to change as refiners search for the most cost-effective methodologies while trying to supply the worlds oil needs. Additive chemistries are under the gun to improve or preserve performance while being more and more restricted in chemistry.

If low entropy involves order and efficiency, higher entropy increases disorder and a breakdown of efficient systems. Rust is a very visual indicator of increasing entropy. New steel shines, is strong and smooth. Rusted steel has lost its luster and become brittle. It seems to me our engine oil development processes are rusting.

There is a glimmer of hope, since entropy can be reversed in a small part of a closed system. I believe wed better start looking for the reverse gear-and soon.

Industry consultant Steve Swedberg has over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society, ASTM International and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at