I was just curious of everyones OCI's and what kind of oil they use. Also, the make of the vehicle would be a plus. I have had great success with 10k intervals on my previous cars with mobil 1. I now want to see just how long i can keep one of my cars. Honestly, i would love to see 600k on my odometer, and my past toyota 4x4 had 419k so i know i can get there! When do you guys change your synthetic?? How many miles do you have?? Any friction related problems yet? My current plan is to run Mobil 1 5w-30 for 10k mile OCI, in a 2003 chevy cavailer 2.2L ecotec. I feel that knowing others OCI's and there stories will help in my decision. Thanks.