Automotive Lubricants



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The Readers Have Spoken 

My wife and I were watching beach volleyball in Laguna Beach, California, on January 1. As the sun set, one player yelled out, “The first sunset of 2020!” And everyone cheered. Well, it’s the end of 2020, and what a year it has been: COVID-19, a presidential election, fires and storms. I don’t know about you, but I’m ready to say good riddance come December 31.  

In the midst of this chaos, you loyal readers continue to ask really pertinent questions. I’ve selected some to share and my answers, plus a few extra comments. Here we go!

The subject of aftermarket additives generated a lot of interest. One of my cronies from the dark ages of additive sales, George Barth in Glen Allen, Virginia, sent me this note about STP Oil Treatment: “Perhaps the greatest and cheapest demo of all time was the old—circa 1970 or earlier—STP screwdriver test [in which you] dip the tip of a large flat-blade screwdriver into a beaker of STP (100% viscosity index improver and chemically a polyisobutene) and then try to grasp the wet tip. It was impossible to hold the screwdriver, even for a muscle bound hunk.” It was a very clever demonstration with very little technical backup, which is sometimes the most effective type. Contrary to George’s view, I was around for this promo.

On a more serious note, Loel Handley in Greer, South Carolina, sent me a letter pointing out the fallacy of pouring an aftermarket treatment into a crankcase and expecting it to mix thoroughly. He noted that he had lost an engine some years ago when a treatment had merely sunk to the bottom of the pan and clogged the oil inlet tube. I could only note my agreement.

Comments from Rain Hein in Tallinn, Estonia, supported my contention that there are few benefits to aftermarket treatments and a world of possible problems. He noted correctly that the use of aftermarket additives normally creates a non-approved product that could not be labeled with any API designation. 

There is one viable concept in the marketplace that includes an additive treatment. Phillips 66’s Kendall GT-1 High Mileage Booster creates an API-approved, high-mileage oil when added to its GT-1 line of engine oils. This treatment can be used during an oil change but not with an oil already in the engine.

In my column about sport utility vehicle lubricants, I reported on the fact that each SUV I test drove had a different recommendation for transmission fluids. I said that with over 100 current specifications, the issue of how to handle a transmission fluid change must be addressed by the industry. Allen Comfort of Warren, Michigan, responded, “I would love to see this for both light- and heavy-duty transmissions. I’ve heard the rationale that transmission designs are so unique that a special fluid is necessary, but I’m not sure I buy it. There has to be some room for standardization in these supposedly unique applications.” 

The variation in viscosity and performance characteristics make it difficult to find common ground. However, I think it is high time the industry does an evaluation of the possibilities. In many respects, this could be no different than varying SAE grades for engine oils.

ILSAC GF-6 was introduced in May 2020. That raised questions about what it meant and, more importantly, how it would be applied. One regular, Blaine Ballentine of Walcott, Iowa, asked what “GF” means. I replied that it stands for gasoline-fueled, at least casually. I’ve never seen an official document that describes it. Remember that GF-6A is confined to SAE 0W-20, 0W-30, 5W-XX and 10W-30. These are the typical viscosities with backwards compatibility. GF-6B covers only SAE 0W-16 and is not backwards compatible. 

Back in 2011, the GF-6 needs statement called for improvements in fuel economy, emissions (less than 600 parts per million phosphorous) and robustness (to prevent turbocharger coking and protect start-stop engines), and for volatility less than 13%. Low-speed pre-ignition protection was added later. The reason it took so long to hit the market was that nearly all of the engine tests were new or significantly revised.

Another regular, Albert Frediani in Chelmsford, Massachusetts, asked me about the recommendations for earlier GF categories found in owner’s manuals for older model year vehicles. His reference was from one of my columns about my 2008 Nissan, which called for ILSAC GF-4 engine oil. He wanted to know if one could find GF-4 oils in the current market. 

This issue is one of the more important aspects of API 1509, “Engine Oil Licensing and Classification System,” requirements. You’ve seen the term “backwards compatibility” on many occasions if you read my column. It is the concept that the latest engine oil categories are compatible with and provide performance protection for engines that require any of the earlier categories, which includes all API designations in the GF, S and C series. So GF-6 covers earlier categories, including GF-4.

How do they do this? The key is the engine test development work and reference oils used in the tests. Let’s face it: Engine oil formulations have used a similar mix of additive components for over 25 years. There are antioxidants, antiwear agents, dispersants, detergents and friction modifiers as well as pour point depressants, viscosity modifiers and antifoam agents in every oil being sold. As the categories became more stringent, the mix and quantities of these workhorse ingredients changed to meet the new challenges placed on them by newer engine designs. 

For example, John Fischer in Palatine, Illinois, raised a question about reducing the antiwear component zinc dithiophosphate in engine oils. I had noted that it was reduced to help improve emissions control, but I neglected to point out that the reason was that ZnDTP could “poison” the catalytic converter, making it ineffective.

Base oil was another topic that brought some interesting comments. This is actually a continuation from last year’s columns. One of the most detailed responses came from Rick Dougherty of ExxonMobil. There has been a great deal of discussion regarding what a base oil is versus a base stock. Rick reminded me that a base oil can be a blend of base stocks, each being produced by a different manufacturer. A base stock is a specific viscosity cut refined by a single producer that owns the branding and specifications. I have to confess that over the years, I have been guilty of interchanging the two terms, as I suspect many old-timers have done.

On another point, Rick also noted that the table that I and others have used to define the level of base stock quality doesn’t actually appear in API 1509. The definition of each group is in text only. As engine oils continue to be improved, the base stock definitions become more important.

Another topic that came up was the changing of brands and chemistries. Michael Atkinson from Victoria, Texas, brought up the subject of randomly mixing or swapping brands of the same SAE viscosity grade of engine oil in the same engine. He noted that a small fleet of light- and medium-duty trucks that he ran for a number of years showed that switching back and forth between brands made a difference. Some engines suddenly started using oil and losing turbochargers. The reverse also occurred. 

Mike also noted that a friend switched to synthetic oil and saw oil consumption increase dramatically, but switching back to mineral oil brought it back to previous levels. He stated that he had seen situations in which vehicles running on mineral oil were switched to synthetics and often showed significant oil consumption increases that did not return to more normal levels after being switched back to mineral oil.

In my response, I noted that switching oils is always a dicey subject. Oil marketers never want you to change brands. Using the same brand assures that you get the same basic chemistry every time. However, oils that meet an API category must be compatible with other oils having similar API licensing. Simply stated, any API CK-4 oil will work when mixed with any other API CK-4 oil of the same viscosity. 

Some major oil marketers believe that their oil should be unsurpassed in performance. Other oil marketers look for the minimum passing requirements for cost reasons. They all meet the spec, but some are robust and others are just OK.

Mike’s comments on oil consumption are particularly interesting. Oil viscosity has been dropping over the past 40 years. In 1980, the biggest segment of the market was SAE 30. SAE 10W-40 was the multigrade leader, and there were slightly more monograde oil sales (52%) than multi-grade. Today, monograde sales are less than 5% of total volume, and multigrade is spread out pretty equally over SAE 15W-40, SAE 10W-30 and SAE 5W-30, with some SAE 0W-20 or 0W-30. A viscosity drop in finished oils requires lower base oil viscosity. Lower base oil viscosity means higher volatility.

Engine design has changed so that lower viscosity is preferred for fuel economy and emissions improvements. In addition, some engines have increased oil consumption, which is really not related to oil as much as it is to design changes. Lately, direct injection, turbocharged, gasoline-fueled engines have shown some increased oil consumption.

Synthetics used to be pretty easy to define. They were basically any material that was chemically produced. Polyalphaolefins and polyol esters are two good examples. However, about 20 years ago, there was a major court decision from the National Advertising Division of the Better Business Bureau in the United States, based on engineering and chemical data, that base oils that had been refined to a significant degree exhibited essentially the same properties as the PAOs and polyol esters in the marketplace. These extra-refined API Group III oils could be advertised as synthetic. That opened the floodgates to a bunch of new “synthetic” engine oils. The products are very good, and many claim they are even better than the old synthetic products. Most of that is the result of improvements in additive chemistry.

As you can see, 2020, in addition to being chaotic, was also the source of a lot of interesting issues in the lubricants marketplace. I wonder what 2021 has in store?   

Steve Swedberg is an industry consultant with 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