I know Honda recommends 0W-20 but I live in the South where it does not get all that cold. Been having some arguments with friends that own Honda vehicles and they are adamant of not using 5W-20. Friends claim the engineers know more than me, which is true. 0W-20 is better for colder climate and my other vehicles use 5w-20 and I buy in bulk. I do my own oil changes and keep receipts for oil filters and oil. Honda filters and I use Mobil 1 5W-20. Friends say it could void my warranty but I don't see how it could. By the way I change oil and filter on 6k mile schedule, just easier for me to keep up with it and always around 30%. What are your takes on this?