
Little background, this is my dads daily driver. Mostly 50/50 city/highway driving. Oil was run from June 14, 2010 to April 24, 2011. Added 5 ounces of make-up in Feb. Oil Filter was a over-sized Amsoil Eao34. I wanted to go 1 year but this is the first run with SSO on a car with over 100,000 so Amsoil does recommend to drain at 17,500. But it looks like it held up very well going past that mark. Sample 1 was PP 5w30 ( here) Currently the car has SSO (bought it just before AZO was released) and same oil filter.