Kirkland Signature Full Synthetic SAE 5W-30 Motor Oil is a premium 100% synthetic engine oil sold in a convenient 6-pack of 1-quart bottles, totaling 6 quarts. Manufactured by Warren Distribution and distributed by Costco Wholesale Corp., this oil meets API SP, SN PLUS, SN, SL and ILSAC GF-6A, GF-5, and GF-4 specifications, making it compatible with a wide range of modern gasoline engines.

The full synthetic formulation provides excellent low-temperature cold-start protection, with a cold crank viscosity of 3,685 cSt at -30°C — well within the SAE J300 maximum of 6,600. It maintains strong high-temperature viscosity (11.02 cSt at 100°C) for reliable engine protection under operating conditions. The viscosity index of 176 ensures stable performance across a wide temperature range. The oil contains robust detergent and antiwear additive packages including calcium (1,342 ppm), magnesium (550 ppm), phosphorus (795 ppm), and zinc (845 ppm), supporting engine cleanliness and wear protection. Molybdenum (80 ppm) and boron (245 ppm) additives further enhance friction reduction and oxidation stability.

This motor oil is designed to maximize fuel economy, reduce wear on critical engine components, and provide long-lasting protection for modern turbocharged and naturally aspirated engines. It has been independently tested by the Petroleum Quality Institute of America and confirmed to meet all SAE J300 specifications for its viscosity grade.