New fuel-efficient API FA-4 oils have lower viscosity, leading some to worry about engine protection. Chevron recently completed a 500,000-mile engine teardown at a Georgia trucking fleet that's been testing these oil formulations for four years.
Chevron Unveils New Delo 400 CK-4 and FA-4 Engine Oils
Chevron unveiled its new line of Delo 400 engine oils meeting the American Petroleum Institute’s new CK-4 and FA-4 heavy-duty diesel oil specifications, offering improvements in fuel economy and engine protection.