Specifically formulated for use in new low-emission, ultra-low-sulfur-diesel engines, Chevron's Delo 400 LE 15W-40 oil is fully compatible with previous API oil service categories and engine models. Keeping rings clean and free for better combustion pressure and minimal wear, the "super-premium-quality" Delo 400 LE is made with Isosyn base stocks, which rival synthetics in critical engine tests, says Chevron.