Just discovered this site last night and wow! What a great source of info on oils. Thank you bobtheoilguy Quick question. Our 1995 Volve 850 Turbo has 90K on it and we just switched over to Mobil 1 10w-30. After perusing some of the posts here, I'm thinking of switching it over to 0w-40 Mobil 1 because it seems that some are of the opinion that it is the "best" Mobil 1. Only concern is that the 10w-30 is so "Higher Mileage Vehicle formula". So would it hurt our car to use the 0w-40 instead? FYI, we live in Ohio which means below freezing winter temperatures and above 90F summer temperatures. About 50-50 street vs highway driving. What oil change interval would you recommend on the recommended Mobil 1? Thanks all.