Im running a 4.0L DOHC 97 Explorer with 195k on it. My typical driving is about 75% city and 25% highway over the course of a 4000 mile OCI. Ford reccomends 5w30 for my truck and I am currently running M1 Ep 5w30. I am thinking of switching to GC 0w30 for the NJ winter (0F-20F usual mins). Any thoughts on this? I was also thinking of adding VSOT to thicken up the oil a bit. Thanks everyone.