Hi, I joined the rest and am currently trying Mobil 1. I want to extend the interval to at least 6k if not 7.5k miles. Given age of my 95 Civic and it has 203,000 miles should I stick to my usual interval of 4-5k miles (previously dino)? I am asking since the motor although it runs pretty well, I'm wondering if an older motor contaiminates oil more easily or causes other issues? Thanks for insight.