Low viscosity oil delivers on diesel engine durability

Aug 07, 2023

The proof is in the data. Lower viscosity, starting at a 10W-30 diesel engine oil and driving down to even a 5W-30 that were question marks back in 2016 when the American Petroleum Institute (API) announced that it had approved two new diesel engine oil standards—API CK-4 and API FA-4—are now tried-and-true, field-tested oils. They are proving that they deliver on engine protection, durability, as well as increased efficiency.

Yet there is still a perception in the industry that you get the best diesel engine protection from a 15W-40; it’s a perception that may be detrimental to the total cost of ownership of your trucks. Steven Bowles, senior product specialist at Citgo, noted that a fleet manager’s focus should be on the engine OEM’s oil recommendations.

“Major on-highway engine manufacturers have been filling engines with 10W-30 for over a decade,” he said during the Fleet Equipment Unscripted interview, noting their confidence in its capabilities. He went on to explain that huge amounts of engine data have been gathered over the years, both from engine tests and lab tests, which prove the efficiency and durability of low viscosity oils.

Bowles noted a field study where a truck ran on FA-4 10W-30 for 850,000 miles with 75,000-mile oil drains. The teardown of the engine after this duration showed minimal wear, indicating that these oils provide good protection.

Couple that with the increased fuel efficiency benefits of low viscosity oils and you have to wonder: What’s holding fleet managers back?

I certainly did. Watch the video above for more on how low viscosity oil is delivering for fleets and engine OEMs.