I am a dealer for Amsoil, which is a pure, 100% synthetic oil that EXCEEDS API standards for SJ and SL. Using the 5W-30 synthetic and using the Amsoil air and oil filters together, you can go 25,000 miles, or one year between drain intervals. Use the Series 2000 Severe Service 0W-30, and you can extend that to 35,000 miles, or one year, with a noted increase in gas mielage as well. Not only do they offer extended drain intervals, they offer protection other oils can't. Amsoil has been around since 1972 and is one of the leaders in the industry. If you would like more information, feel free to drop me a line at [email protected]