While SAE 10W-30 motor oils used to dominate the market, SAE 0W-20 has emerged in recent years as the fastest-growing viscosity grade in Europe and North America. In Europe, SAE 0W-20 and 0W-30 are increasingly being recommended, even for vehicles that previously required SAE 5W-XX.

However, widespread acceptance of viscosity grades below 0W-20 has not yet materialized, despite discussions and developments in the industry. It may still be too early, or there may be obstacles limiting growth.

Trends in Motor Oil Viscosity – Is 5W-30 a Thing of the Past?

Historically, the development of lower viscosity lubricants was driven by the aim of improving fuel efficiency, as the use of low viscosity motor oils helps reduce fuel consumption and emissions. These development directions were previously highly dependent on the availability of suitable base oils for the production of such motor oils, as the initial production of SAE 0W-XX products was limited to the use of Group IV base oils with a high viscosity index by lubricant manufacturers.

However, the increasing use of Group III base oils, which have similar properties to Group IV base oils but are more cost-effective and also possess a high viscosity index, enabled vehicle manufacturers to leverage the benefits of lower viscosity lubricants.

Until around 2009-2010, it was not common for major global automakers such as Honda and Toyota to widely recommend the use of SAE 0W-20 motor oils outside of Japan. Other vehicle manufacturers only began to follow this trend in their lubricant recommendations over the past decade.

Honda first recommended the use of 0W-16 viscosity motor oil in 2009, at a time when the xW-16 viscosity grade was not yet defined in the commonly used SAE J300 viscosity standard. The SAE J300 standard has since been revised twice, once in 2013 and again in 2015, to include additional ultra-low viscosity grades such as SAE 0W-12 and SAE 0W-8 to meet the needs of vehicle manufacturers.

Major lubricant manufacturers like Shell and Exxon Mobil predicted as early as the early 2010s that SAE 0W-20 would be the fastest-growing viscosity grade in the coming years, surpassing the still-popular viscosities of 0W-30 and 5W-30. Initially, growth was expected for 5W-20, but vehicle manufacturers quickly shifted from 5W-20 to 0W-20 motor oils. As turbocharged engines became more widespread, the number of vehicles that still required the use of 5W-30 motor oils also increased, but 0W-20 has since become the most common viscosity for newly sold vehicles.

In addition to 0W-20, motor oils with even lower viscosities such as 0W-16, 0W-12, or 0W-8 have been available for years, but their spread has not gained significant momentum. From a performance perspective, SAE 0W-20 offers an ideal balance between engine protection and fuel efficiency.

How much can the viscosity of motor oils for internal combustion engines be reduced?

How low can oil viscosity reasonably be reduced? SAE 0W-8 is probably the lower limit, although there are studies that describe even lower viscosity grades, such as SAE 0W-4.

The use of SAE 0W-8 products has so far been limited to some hybrid vehicles and has mainly been used in the Japanese market. Today, it appears that viscosity grades below SAE 0W-20 are used in specific applications, such as in hybrid drivetrains with small engines. However, if these motor oils with viscosity grades below SAE 0W-20 are not more widely accepted by vehicle manufacturers, they will remain niche products, primarily available in car dealerships for specific vehicles.

A large portion of representatives in the lubricant market state that it is difficult to predict, but it currently seems unlikely that viscosity grades below SAE 0W-8 will be needed. Vehicle manufacturers are utilizing the last remaining efficiency potentials in design and technologies, including the use of hybrid drives and electrification, to improve the fuel efficiency of their vehicles.

They determine the viscosity grade of the motor oil that they believe provides the right balance between fuel efficiency and engine protection. Technical challenges for motor oils, such as the evaporation requirements outlined in current lubricant specifications, must still be met even if lower viscosity grades are desired by vehicle manufacturers.

It is noteworthy that the SAE J300 committee has decided not to define any grades below SAE 0W-8 for the time being, at least not until their definition becomes commercially necessary.

Infineum, one of the largest developers of lubricants, emphasized that the biggest current challenge lies in the viscosity of the motor oil and its evaporation. Further reduction of viscosity would require significant developments in both additives and base oil production. The shift to fully electric vehicles makes the widespread use of low-viscosity oils unlikely. Given the limited efficiency gains and the need for engine protection, it is currently unlikely that the viscosity of motor oils will be reduced further.

Replacing 5W-30 Motor Oil with SAE 0W-20

Although the future is uncertain, SAE 0W-20 is expected to become the leading viscosity grade worldwide in the coming years and the main grade by 2030. The shift to lower viscosity grades such as SAE 0W-16 or 0W-12 will remain limited, as SAE 0W-20 is considered the optimal balance between efficiency, longevity, and emissions reduction.

Lower viscosities in turbo engines would require new platforms and expensive technologies. However, due to the focus on electrification, the industry lacks the resources and motivation to pursue such developments.

The trend is moving toward lower viscosity grades, and the demand for 0W-20 is expected to increase significantly and dominate by the end of the decade. Viscosity grades like 0W-8 and 0W-16 will remain limited to specific applications and niche products.