Originally Posted by GMBoy
I have been involved in GM engineering of these SUV's since the 800 series. I know them. With that I can assure you these K2xx (2015-2020)and the new T1 (2021+) are totally engineered around 0W/20 oil. I would not even consider a thicker oil based on the strategies in the ECM software. Maybe when these are older and worn out you can go to a 5w/30 but trust me - 0W/20 is fine and protects fine. The engines were meant for this. It is not like a RAM Hemi or 3.6 Pentastar where they went from 5w/30 to 5w/20 on the same identical motor. GM did 0W/20 on purpose. FCA did it just to squeak some more miles per gallon out. No mechanical or programming need for the 5w/20 in those motors. Having said that, I would NOT go running a 0W/20 in your 900 series (2007-2014) GM truck just because you think you have the same 5.3/6.2 motor because you don't. Keep 5W/30 in those engines.
It is very hard for some of us to accept low weight oils, I get that. However, we on BITOG are not smarter than the engineers who built the motors. I know these guys and they know what they are doing. I have had the thick vs thin oil discussion several times with them. No for the big question you may have....will running 5w/30 do harm in these 0W/20 spec motors? NO. But try running thicker oil like 15w/40 or 20w/50 and you WILL have issues from AFM activation, less MPG, higher oil temps and less power. Again - keep with the recommend oil in the case of the new GM DI V8's. You are better off. On the flip side - running 5w/30 in your 5.7 Hemi and 3.6 Pentastar is better. They were designed around that weight from the start.
Thanks for chiming in! Given your experience with the platform, are there any trouble spots I should keep an eye on? Not only oil related, but in general.