When any new heavy duty engine oil performance category is introduced, plenty of attention is drawn to the testing protocols that a new engine formulation must pass in order to be certified. These engine tests help certify necessary performance, ensuring that a new generation of lubricants will meet the needs of modern engine hardware.

But it’s natural to wonder: Engine tests are one thing—what about real-world performance?

For fleets around the country, this is an especially important question to ponder as engine oil technology continues to evolve. The most recent American Petroleum Institute (API) performance category is split between API CK-4 and FA-4. FA-4 certifies lower-viscosity engine oils specifically formulated to deliver enhanced fuel economy benefits for modern engine hardware. And right now, work is being done on a new performance category that will replace CK-4 and FA-4 in the coming years, and it’s expected that the technology required for new formulations will be even more advanced.

So, how does the lubricant industry ensure that brand new lubricant formulations will offer the performance the fleets require from their day of first license? This is the story of how lubricant formulators ensure performance—not just in the lab, but in the field.

An Extensive Testing Process

In the years since CK-4 and FA-4 were proposed as a new category—nearly ten years ago—additive companies, oil companies, and OEMs have generated hundreds of millions of miles on lower viscosity oils and API FA-4 oils in real world field testing. Such testing has covered all major OEM engines in a wide variety of duty cycles.

Initial development of a new category involves a series of experimental tests to determine the most reliable ways to certify the kind of performance level the category will require. This process requires significant investment—of both time and resources—to establish the parameters of the new category, helping to satisfy the needs of evolving engine hardware. Experts develop initial formulations, which are then carefully tweaked to achieve the necessary levels of performance. Testing is carried out on real engines and a full dynamometer, a process carried out by various industry stakeholders. For example, through the development of CK-4 and FA-4, Lubrizol performed extensive dynamometer testing at its Wickliffe, Ohio, headquarters.

While this process continues, real-world field testing is performed simultaneously. At Lubrizol, our teams work closely with a number of fleet operator partners to supply them with formulations that have proven effective in bench and dynamometer testing. Typically, all our teams require is that these fleets change their oils at regular intervals and take samples they can submit to our teams every two weeks for analysis.

We perform this kind of analysis with lubricants that have run in trucks all around the United States, because we know that some miles are more severe than others. Heavy duty service is not as strenuous in the Midwest as it is in the Rocky Mountain region, for example. Throughout all this work, our teams are primarily seeking to identify any premature engine wear that may have resulted from the lubricant performance. We look at the oil itself to identify any potential premature oxidation or unwanted viscosity increases.

Over the course of the category’s initial development to today, we have field-tested FA-4 lubricants in more than 400 individual engines over the past decade, generating over 70 million miles of data. Trucks our teams have tested include new models designed to be filled with FA-4 lubricants, and older-model trucks where FA-4 is not specified by the manufacturer. Through this testing, we have seen heavy duty fleets achieve significant fuel economy savings all while providing their trucks with outstanding protection.

Applying FA-4 Lubricants

With the knowledge of how robustly FA-4 formulations have been field tested before hitting the market, fleets should have the confidence to explore selecting these lubricants in order to reap the benefits they have the potential to provide.

For example, it's been shown that Class 8 over-the-road fleets can realistically expect fuel savings in the range of 0.5%–1.5% by switching from an API CK-4 certified 15W-40 formulation to 5W/10W-30 engine oil (Worth noting: 15W-40 lubricants make up the majority of the market share). In addition, the savings from switching to the fuel-efficient API FA-4 variant can be expected to add a further 0.4%–0.7% of increased fuel efficiency.

For any fleet looking to enhance its overall efficiency, it’s worth investigating how adopting lower-viscosity lubricant formulations can help. If you’re interested in seeing the potential, start the conversation with your oil supplier about running some testing of your own, where you can see the impact for yourself.

The bottom line is that FA-4 lubricants are one of the best ways fleet managers have to boost fuel economy and save on cost. Extensive testing proves it.