I've got a 2000 Silverado with a 6.0L, purchased at 110,000 and currently with 265,000 miles on the clock. I've been experimenting with different Rotella viscosities as they also work in my motorcycle that needs a JASO MA rating ('89 KLR 650). I do some stop and go driving and will start commuting approximately 1:15 hrs for work. The owner's manual recommends 5W-30 for all temps and 10W-30 for above freezing. I live in Maine and the amount of time when morning temps are at or above freezing only lasts a few months.
This engine has the infamous 6.0L "knock" on cold startups. It's done this since I got the truck at 110,000 miles. I base oil changes and suitability of oils for this engine on the amount of knock on startup. Rotella T, T5, and T6 have excelled in this category; Mobil 1 syn, NAPA brand, and Castrol GTX have not. Rotella T are the only oils that haven't had reduced OP towards the end of an oil change interval.
I'm currently running T6 5w-40. It held up great over the winter with startups commonly around 0F, and occasionally into negative teens and twenties. I'd like to keep running the T6 in both of my machines. The issue is when warmed up my oil pressure runs at minimum 40 PSI, and when on the highway (2000-2300 RPM) OP is between 55-60 PSI. I'm assuming there is a high pressure shut off that keeps pressures below 60, as I've never seen it above that mark. Is the 5W-40 too thick? What are some recommendations for other HDEO's?
Thanks, Joe
This engine has the infamous 6.0L "knock" on cold startups. It's done this since I got the truck at 110,000 miles. I base oil changes and suitability of oils for this engine on the amount of knock on startup. Rotella T, T5, and T6 have excelled in this category; Mobil 1 syn, NAPA brand, and Castrol GTX have not. Rotella T are the only oils that haven't had reduced OP towards the end of an oil change interval.
I'm currently running T6 5w-40. It held up great over the winter with startups commonly around 0F, and occasionally into negative teens and twenties. I'd like to keep running the T6 in both of my machines. The issue is when warmed up my oil pressure runs at minimum 40 PSI, and when on the highway (2000-2300 RPM) OP is between 55-60 PSI. I'm assuming there is a high pressure shut off that keeps pressures below 60, as I've never seen it above that mark. Is the 5W-40 too thick? What are some recommendations for other HDEO's?
Thanks, Joe