VSP News: Uptime Update, Episode 34 – Lower viscosity diesel engine oils

Sept. 27, 2019
Dan Arcy, global OEM technical manager for Shell Lubricants, shared insights on the continued shift in specifying lower viscosity engine oils for heavy duty engines.

As engine technologies improve and become more efficient, low viscosity engine oils are continuing to become more prevalent for fleets. Lower viscosity engine oils have been touted as a way to help improve fuel economy, while still providing the necessary engine protection offered by traditionally higher viscosity oils like 15W-40. Dan Arcy, global OEM technical manager for Shell Lubricants, shared insights on the continued shift in specifying lower viscosity engine oils for heavy duty engines.

Transcription of interview:

Erica Schueller, Fleet Maintenance: Hello and welcome to VSP News: Uptime Update. I am your host Erica Schueller, Editor-in-Chief of Fleet Maintenance magazine, covering all maintenance, all vehicle classes, all management, all the time. 

Lower viscosity engine oils have been touted as a way to help improve fuel economy, while still providing the necessary engine protection offered by traditionally higher viscosity oils like 15W-40. As engine technologies improve and become more efficient, low viscosity engine oils are continuing to become more prevalent for fleets.

I talked with Dan Arcy, global OEM technical manager for Shell Lubricants, about the continued shift in specifying lower viscosity engine oils for heavy duty engines.

We first discussed the changes in engine designs over the last few decades, and how these changes have impacted a shift in the requirements of heavy duty engine oils.

Dan Arcy, Shell Lubricants: There have been a number of changes made in engines over the past few decades, and they have a direct relationship to the oil and what’s changed there as well. In fact, I’ve been working in this industry for over 30 years and there are a lot of changes that have taken place. We’ve seen engines that used to have drain intervals of 10,000 miles.  

Now, through the advancements of different types of materials in the engines, different metallurgy, things like [high-pressure] common rail systems, and advancements in engine oil, we are now seeing oil drain intervals of 75,000 miles for these same types of vehicles.

The improvements in engine designs and oil formulations have led to improvements in durability for these engines.

When I started, again, it used to not be uncommon to have to do a rebuild, or a partial rebuild, at 250,000 or 300,000 miles. Now, many engines are going out well beyond 1 million miles.

Schueller, Fleet Maintenance: Continually more stringent federal regulations, intended to help reduce vehicle emissions, have directly influenced the operation and design changes of heavy duty vehicles. 

Arcy talks about how these design changes have impacted engine oil composition and usage to both help improve fuel economy and provide more durability.

Arcy, Shell Lubricants: With the latest changes in emissions standards, one of the things that has changed is that there are now requirements for improvements in fuel economy, which will lead to a reduction in CO2 [carbon dioxide] emissions. 

With the new engine oil standards – API CK-4 and API FA-4 – this allows engine manufacturers to run their engines in a way that can provide an improvement in fuel economy.

In fact, at Shell, we’ve done a lot of testing. For moving from an SAE 15W-40 engine oil to an SAE 10W-30 CK-4 engine oil, we’ve seen fuel economy gains of up to 2 percent.

In addition, with the new standards, we’ve seen if [a fleet moves] from a SAE 15W-40 engine oil viscosity to an FA-4 SAE 10W-30, we’ve seen fuel economy benefits of up to 2.6 percent.

If every truck saved 1 percent on fuel economy, we would save over 1 million gallons per day in fuel consumption. This can translate into a significant savings in CO2 emissions as well. For every gallon of diesel fuel that you burn, you generate about 22.38 lbs of CO2. Again, that would be 22.38 million lbs of CO2 saved every single day if we all got just 1 percent better fuel economy.

Schueller, Fleet Maintenance: What changes have been made to engine oil specs to accommodate the more efficient diesel engines? And, why are there still multiple specs to replace CJ-4 standard oils? Arcy shares more information about the API engine oil standards.

Arcy, Shell Lubricants: In December of 2016, API came out with two new engine oil standards: API CK-4 and API FA-4. API CK-4 oils were an improvement over the previous category, which was API CJ-4. API CK-4 oils provided improvements in areas like high-temperature oxidation control. These oils were the same viscosity grades that we had with API CJ-4. 

However, the big advantage of going to these new engine oil standards is the higher performance allowed for engine manufacturers to run engines at higher temperatures so they would be more efficient, and it allowed an increase in drain intervals for many engines.

In addition to that, a second standard came out: API FA-4. These are lower viscosity engine oils that provide some additional fuel economy benefits while maintaining durability.

Not all engines at this time allow the use of API FA-4 oils. But those that do can take advantage of the additional fuel economy benefits.

Schueller, Fleet Maintenance: As our industry continues down the path of improving fuel economy and vehicle efficiencies, we can certainly expect changes to engine oils too. 

Arcy shares his thoughts on what he expects down the road, as it relates to heavy duty engine oils, and lower engine oil viscosities.

Arcy, Shell Lubricants: For many years, an SAE 15W-40 engine oil was the primary viscosity grade. A number of years ago, many engine manufacturers started to move to lighter viscosity grades like SAE 10W-30s. These provided some fuel economy benefits, without any concerns about durability. 

We’re seeing the same thing going forward with engine manufacturers and more of our customers going to a lighter viscosity grade to take advantage of fuel economy benefits.

In the future, we’ll continue to see lighter viscosity engine oils, as the engine technology and oil technology continues to improve. Again, these will lead to improvements in fuel economy and a reduction in emissions.

Schueller, Fleet Maintenance: If you’d like more information on current trends in heavy duty engine oils, visit the link below to read a recent feature story from Fleet Maintenance on this topic.

That’s it for this week! Thank you for tuning in to VSP News Uptime Update, I’m your host, Erica Schueller.

Until our next broadcast, keep up with this, and other industry topics, by visiting us online at VehicleServicePros.com.

Photo courtesy of ExxonMobil Lubricants
Used oil analysis is a process in which a fleet takes a sample of used engine oil from the vehicle and sends it to a laboratory to be analyzed.