Viscosity Trends

Historically, development of lower-viscosity lubricants has been driven by the quest for improved fuel economy, which reduces emissions and consumes fewer resources. It also depended on the availability of the appropriate base stocks to enable and meet demand for these products. SAE 0W-XX products were once limited to API Group IV, high viscosity index-type base stocks. But the growth of comparative, lower cost, higher viscosity index Group III base stocks has enabled OEMs to take advantage of benefits from lower-viscosity lubricants. 

It was 2009-2010 before Honda and Toyota began to widely recommend SAE 0W-20 in North America. General Motors and others have followed in the past decade. 

“Infineum has been active in developing robust lower-viscosity [passenger car motor oils] for over 30 years,” said Dan Pridemore, Infineum industry liaison manager of North America. “When Honda first launched a fuel-efficient SAE 0W-16 oil in 2009, XW-16 was not yet a defined SAE J300 viscosity grade. SAE J300 has now undergone two revisions—in 2013 and again in 2015—to support the need of OEMs to define and recommend viscosity grades as low as SAE 0W-8.

“Lower-viscosity PCMO fluids have undergone extensive testing, including certification for API and JASO licensing, with OEMs recommending these grades for engines which are designed to work efficiently and optimally with these products,” Pridemore added. 

“Shell has seen enormous growth in SAE 0W-20 over the past 10 years,” said Jeff Hsu, North American PCMO technology manager for Shell. “We would expect it to become the largest-selling viscosity grade in North America and around the world, overtaking SAE 5W-30. In the past, we thought SAE 5W-20 would overtake SAE 5W-30, but numerous OEMs quickly moved from 5W-20 to 0W-20, and the latter can service most cars that once called for 5W-20. Turbo-charged engines have increased in the market, and they mainly call for SAE 5W-30, which will also continue to be heavily marketed.”  

Hsu continued: “In terms of lighter SAE grades, 0W-16 has been around for several years but has not seen rapid adoption in the market and has failed to gain traction with distributors, service providers or end users. From a performance perspective, SAE 0W-20 is an ideal balance to both protect the engine hardware and deliver improved fuel efficiency for most new vehicles.”

What is also evident is that the technology to advance these products has been available before the industry’s ability to supply the products in a complex and competitive supply chain. In the past, the industry has tended to evolve to one widely used viscosity grade, then that grade dominated the supply chain for about 10 years.  

Back in the 1980s, the dominating grade was SAE 10W-40. In the 1990s, SAE 10W-30 was the fastest growing viscosity grade and peaked around 2000. This was followed by SAE 5W-30 and to a lesser degree SAE 5W-20. SAE 5W-30 recommendations more broadly started in the early 1990s in North America and did not reach its peak until around 2010. 

Supply Chain Is King

It takes time for the car parc to age before a new viscosity grade can significantly grow and fully impact supply chains. Today, we have three major PCMO viscosity grades in use: SAE 5W-30, 5W-20 and 0W-20. It is clear that we are seeing obsolescence of SAE 10W-XX and higher grades in the PCMO market. What is not evident is if SAE 0W-16 or lower will grow at the pace that SAE 5W-XX once did or that 0W-20 currently is.

There can be many reasons for this, and the supply chain is one. Today, most consumers buy an oil change service, and those service providers want to purchase lubricants in bulk. But distributors and providers have limited tankage to keep inventory in bulk, and it gets expensive and more complex to handle smaller packages.  

Complicating things further, SAE 5W-30 fluids have conventional and full synthetic iterations, the latter meeting GM dexos1. “For SAE 0W-20, our research has shown that most installers want an SAE 0W-20 that works in most cars they service,” said Tom Glenn, President of Petroleum Trends International and Petroleum Quality Institute of America. “They prefer a PCMO that meets the needs of essentially all Japanese OEMs and meets GM’s dexos1 specification. This means a one-size-fits-all fluid they can manage in bulk.”  

Research shows that this would not be true for a Honda or Toyota dealer that does not need the GM level of performance and likely could get a more basic SAE 0W-20 fluid for lower cost. Since SAE 0W-XX still requires advanced Group III base stocks, the cost difference is not as large as that for 5W-XX oils in which a conventional product can use a Group II base stock and a full synthetic a Group III one. 

“As SAE 0W-20 grows, marketers will look to differentiate this viscosity grade as it has done for legacy SAE grades,” Glenn said.

With the rise of hybrid electric vehicles, OEMs have specified even lower viscosity, but the operating conditions for hybrid engines differ from a more conventional, sometimes turbo-charged internal combustion engine. This subset of vehicles can safely use even lower-viscosity products because engine operating temperatures are lower and there is less concern about oil consumption via volatilization.   

This has fragmented recommendations and makes supply chains for providers more complex. This may pose a barrier to cost-effective availability of products to meet the needs of some vehicles in the marketplace. 

“Supply logistics are typically a challenge when new viscosity grades emerge. While products may be available, purchases could require mixed pallet shipments, minimum orders, slow inventory turns, and other less than desirable logistical concerns,” Glenn said. “But one thing for sure is that where there is demand there will be supply, even for some of the niche products servicing hybrids and other vehicle types requiring such emerging viscosity grades and performance levels. While it’s unlikely many, if any, installers will be filling bulk tanks with 0W-16 and other lower-viscosity grades anytime soon, we will see such products showing up in bays as packaged goods, such as quarts and flex packs. You can also be fairly certain oil changes requiring such grades will command a premium price.”

How Low Can Viscosity Go?

So how low can viscosity reasonably be pushed? SAE 0W-8 is likely the limit, although there have been papers describing even lower viscosity grades, such as SAE 0W-4. 

“The industry has been discussing lower-viscosity grades even before they were formally adopted into SAE J300,” Hsu said. “So far, products like SAE 0W-8 have been limited to some hybrids and mainly in Japan. Today, it appears that grades below SAE 0W-20 will have targeted applications for small engines seen in HEVs. But unless these products are adopted across a wide spectrum of OEMs and vehicles, they are unlikely to be more than niche oils, sold mainly at dealerships for specific vehicles.” 

Hsu continued: “The market in North America favors products that can be handled in bulk, such as SAE 5W-30 and 0W-20, and with industry and OEM claims that can service most vehicles on the road. Niche products will be significantly more costly due to being in smaller packages” with slower inventory turns. 

Pridemore agreed that PCMO viscosity can only be pushed so low. “Though it’s challenging to predict, it appears unlikely today that viscosity grades lower than SAE 0W-8 will be needed,” he said. “OEMs are capturing the last remaining efficiencies through modified designs and hardware, including hybrids and electrification, and specifying the viscosity grade fluid which they believe provides the correct balance of efficiency and protection for their engines. Technical challenges, such as complying with the volatility requirements in today’s lubricant specifications, must be addressed should even lower-viscosity grades be required.”

It is worth noting that the SAE J300 committee elected not to define grades below SAE 0W-8, at least until it can be commercially demonstrated. As noted by Infineum, balancing viscosity with volatility would be a key challenge and require significant innovation in terms of additives and base stocks.  With OEMs shifting focus to battery electric vehicles, increasingly lower-viscosity products are highly unlikely when considering both the need to protect engine hardware and diminishing returns from fuel economy improvements by further nominal reductions in viscosity. 

“SAE 0W-8/12 can be used without a major engine hardware change in natural aspirated engines,” said Mike Alessi, technology integration manager at ExxonMobil. “Those engines are becoming more and more limited compared to turbo-charged engines. Those viscosity grades are expected to be used in hybrid and non-hybrid applications of Japanese builders. However, as OEMs shift to turbo-charged engines with smaller displacement to improve fuel economy, it is expected that SAE 0W-20 will be the dominant grade.”

Infineum’s 60th Anniversary of Infineum Trends provided an outlook for viscosity grade trends through 2032. “SAE 0W-20 is a commonly used factory fill and recommended service fill viscosity grade today,” said Pridemore. “In North America, while SAE 0W-20 oils only represented 5% of the market in 2016, their market share was close to 25% in 2020 and is projected to grow further to around 50% by 2030. SAE 0W-16 and lower viscosity grades are likely to remain niche through the end of the decade.” 

It should be noted that as viscosity trends lower, the demand for higher viscosity index base stocks will grow at the expense of lower viscosity index ones. In more familiar terms, Group III, Group III+ and Group II+ will be in high demand.  More conventional Group II demand will replace any remaining Group I demand globally, and Group I will largely disappear from engine oils.

While the future is always uncertain, it appears to be a safe bet that SAE 0W-20 will become the leading viscosity grade globally. 

“SAE 0W-20 is growing rapidly, and it is expected to be the main viscosity grade by 2030,” Alessi said. “Migration to lower viscosity grades like SAE 0W-16/12 will be limited as most OEMs see that SAE 0W-20 strikes the right balance between fuel economy, durability and particulate emissions. Going to lower viscosity in turbo-charged engines will require new hardware engine platforms and new expensive lubricant technology. However, with energy transition and focus on electrification, OEMs and industry have little appetite and resources to develop such new platforms needed to lower viscosity.” 

New specifications that may be implemented will have little impact on viscosity grade trends, which are influenced by OEM recommendations and rarely impacted by new industry specifications. ILSAC GF-7 is expected to be implemented by 2025, and it is worth noting that GF-7 will not cover SAE 0W-8/12. (API may license them, but there will be no ILSAC certification mark.) OEMs choosing to specify these grades will use JASO or IFC-recommended products, at least in the near term. How that fits into the North American system and widely recommended ILSAC system is yet to be determined. 

The Bottom Line

PCMO has migrated to lower viscosity grades. While there are currently three major grades in the North American market—SAE 5W-30, 5W-20 and 0W-20—demand for 0W-20 is expected to rapidly grow and become the leader over the next 10 years. Although 0W-8 and 0W-16 are on the radar, these and other grades will have targeted applications and remain niche products. As demand for SAE 0W-20 grows, so will demand for Group III base oils.  

Steve Haffner is president of SGH Consulting LLC. He has over 40 years of experience in the chemical industry, primarily with Exxon Chemicals Paramins and Infineum USA. Contact him at sghaffn2015@gmail.com or 908-672-8012.