I change the oil on all my kids cars. I use Mobil 1 and 7500 mile OCI. My daughter has a 2004 Chevy Malibu Maxx (3.4 liter V6)with 78,000 miles on it. We usually go by the OLM and change oil at about 6,800 miles. Well, last time she made some trips and it was 9,000 miles (well over OLM). I remember when BITOG did a test on a Chevy LS1 that went 18,000 miles (with 1,000 mile UOA) on Mobil 1 before needing changed (they changed oil filter at 11,000 miles). So, I guess this is okay? Opinions?