GM has been running the 6.2L/10 speed/0W20 combo for 8 years now. Based on 13.6K miles per year, the first 3 years of production have 80-110K miles on them now. How come we are not seeing tons of issues with these engines?
vcode,
You clearly do not understand the situation and bearing loading issues at play here. While billions of vehicles in your mind run 0W20 without issue so therefore it is fine for the 6.2l configured in these large SUV is also adequate, it is not. Engine reliability and longevity take a far back seat to fuel economy due to requirements the auto manufactures need to meet.
0W20 was formulated for 2 primary reasons, increase fuel economy and probably as a side benefit reduced parasitic loading on the engines so they will provide better fuel economy and will put out more power due to the lower parasitic oil drag. BUT, this comes at a cost and there are LIMITS at to the benefits and there is a reduction in safety margin for engine protection and in higher loading situations 0W20 is not sufficient.
There are so many variables at play here they cannot all be accounted for. Your lighter weight mid size sedans with 4 and 6 cylinders, 0W20 may be fine, but for these 6000 lb bricks its not.
You also have no history of the V8 early failures beyond warranty, many people do not even speak up about these issues, often they either pay for the repair or trade the vehicle in and move on.
There clearly were more problems for the 6.2l from 2021-2025 due to manufacturing issues. But if these engines were using something other than 0W20 there would be far fewer failures. Look what GM is doing on the recall.
A lot of things have changed, these engines are NOT designed for 0W20 oil, if they were, they would still be using polymer coated rod bearings, they still use polymer coated main bearings, the oil pump would be like the current generation L84 5.3l engine with is a variable displacement SINGLE stage variable displacement oil pump, unlike the stupid DUAL stage variable displacement oil pump that the L87 6.2l is still using, again due to fuel economy, not engine reliability and longevity. The DUAL stage oil pumps do not command the increase in oil pressure until around 3000 RPM where these engines rarely operate unless accelerating on to an on ramp at a pretty brisk pace or passing at a pretty good rate on the highway. The 5.3l benefits from the SINGLE stage oil pump and has more oil pressure at lower RPM then when compared to the 6.2l with the DUAL stage oil pump.
If you would perform the calculations for bearing loading the why the 5.3l and 6.2l operate in these large SUV's you would see 0W20 is marginal at best on the 5.3l and really not adequate for the 6.2l with regard to oil shear. The 5.3l would be far better off running at least 5W30 and the 6.2l is better off running 0W40.
If GM would go back to the polymer coated rod bearings and SINGLE stage variable displacement oil pump, 0W20 would work better for the 6.2l but without a lot of testing who knows by how much of a margin.
While bearing materials have changed quite some time ago, lead and even copper has been pulled out of many of the newer bearings. Most are now harder Bi-metal Aluminum bearings which are far less forgiving than the older tri-metal copper/lead/tin bearings. The Bi-metal aluminum bearings tend to shed or peel like an onion when overloaded and/or oil starved, again very little margin for error. This is why some of the coated bearings are far superior for heaving loading and thin oil. But the real problems is the ultra thin oils are being used in applications where they are not ideal.
Do what you want, I am running 0W40 oil with a Range DFM and Auto Stop/Start delete unit and consistently getting almost 19 MPG on the highway driving hard. Speeds often close to 80 MPH. When I slow down and drive easier I have seen my fuel economy hit over 21 MPG on the highway. My lifetime fuel economy on the truck is 17.6 MPG which includes all in town/city and highway driving. So I do not see any significant hit in fuel economy with the way my vehicle is currently configure.
Again, anyone running 0W20 on the 6.2l is not doing their engine any favors.