I just build and installed a new 6.0L in my 2001 GMC Sierra 4x4. I built it with 11:1 compression and about 500HP at the crank. I broke it in with Rotella dino 10w-40 plus a break-in additive. I've changed the oil at the following mileages. 10, 100, 500, and 1500. I now have about 3300 miles on it and am ready to change it again. I had to add about 1/2 quart of oil in the last OCI.
Now the big question. Am I ready for synthetic, or do I need to continue break-in with the dino?
If ready for synthetic, which one? Bearing tolerances in the engine are to factory specs. With the 10x-40, I'm running about 53 PSI oil pressure at idle, 60-65 on the interstate, and probably 75-80 PSI at redline. I previously was running M1 TDT 5w-40 in my old 5.3. I have Castrol Edge in another vehicle, and PP in another. I'm not brand loyal, just want the best oil for my truck.
Now the big question. Am I ready for synthetic, or do I need to continue break-in with the dino?
If ready for synthetic, which one? Bearing tolerances in the engine are to factory specs. With the 10x-40, I'm running about 53 PSI oil pressure at idle, 60-65 on the interstate, and probably 75-80 PSI at redline. I previously was running M1 TDT 5w-40 in my old 5.3. I have Castrol Edge in another vehicle, and PP in another. I'm not brand loyal, just want the best oil for my truck.