Have a 95 Landcruiser with 130K miles. For the last 100K miles I have used Mobil 1 5w30 and alway the Toyota oil filter, it has never used any oil between changes (6K miles). A buddy at the gym convinced me to try Amsoil Synthetic 5w30. With the Amsoil I have had to add 1 1/2 qts in the last 5,600 miles. Whats the deal with the oil useage with the Amsoil? (the truck does not leak any oil) I am coming up on the 6K mile oil and filter change interval and I'm thinking about going back to the Mobil 1 5w30 since my truck did not use any oil between changes with the Mobil 1. What would you do?