Im gonna ignore my OLM during heavy towing with my 2008 silverado vortecmax. During long hill climbs I see my oil pressure dropping due to heating up of the oil, I am not seeing that 10 psi per thousand rpm rule during this kind of towing. I also pulled the dipstick when refueling and burned my hand horribly on the stick and saw some smoke coming from the dipstick tube!! I still cant believe the gm calls for a 5w30 under all conditions in these trucks. I am running Pennzoil Platinum 5w30 by the way. I got 3200 miles on this oil at 60 percent on the OLM. I also run an aftermarket computer tuner on this truck. I will run a UOA at around 4 or 5 thousand miles and see from there how much longer I can punish this oil. Im thinking at least a 10w30 with a bit higher HTHS and volitility will help in the summer months. Synthetic 10w30 flows better then conventional 5w30 at startup if I am not mistaken? What does everyone think??