Hey guys I want to change oil in my 6.4 the truck has 106k on it. My question is what kind of oil and weight do you guys recommend? Also should I go synthetic or not also what weight? I know it's wintertime and I live In South west pa. My question is if I would go with a lighter weight oil for wintertime how warm can it get outside before is gotta change the oil back for the summer time? Reason is I don't out that many miles on my truck every day. I work 60 miles round trip to and from work. Let me know you guys suggestions. Also is there any additive you guys add into your oil or just oil? Thanks for your time and help guys.