Okay Folks, I have searched all over, and I didn't see this specific question addressed. (and forgive me for having already sort of explored this question in another person's posted question regarding mixing of the two grades.)
My 2019 Equinox (1.5L turbo engine) specs 0W20 oil. I really believe that 0W30 would be a better choice.
After way too many days of researching all over the 'ole interweb, I have concluded that 0W30 will afford better engine wear protection at normal engine operating temperatures.
Both of them have a "Winter" rating of "0", so until the engine reaches it's normal operating temperature both oil grades are essentially identical. However after the engine reaches normal operating temperature the pictures is quite different. The hot viscosity (100 degrees C) for the 0W20 is between 5.6 and 9.3 centistokes, and the 0W30 is between 9.3 and 12.5. And from all the research I've done, it appears that from a mechanical engineering standpoint, motor oil viscosity of about 10 or 11 cSt is ideal for the vast majority of automotive engines. -for at least the last 40 or 50 years.
For the American auto engines, 10W30 was pretty much the standard from about the 1970's through the 1990's, and then around 2000 5W30 became the norm. But now with the government fuel economy standards squeezing blood out of the industry and engine displacements getting very much smaller (and hopefully with more precisely controlled tolerances) the 0Wxx oils are apparently the new normal.
I find this fact quite interesting: When GM starting using these 1.5L turbo engines in 2016 the oil spec was 5W30. It seems to have magically changed to 0W20 in 2018. I have researched OEM GM part numbers for many of the internal engine parts used in these engines, especially the parts where oil clearances are critical. And from 2016 through at least 2019 the part numbers are identical. Looks to me like the popular reason/excuse given for switching from 30 weight hot to 20 weight being because of so-called tighter tolerances is -V--E--R--Y- questionable. How about this reason: C.A.F.E standards. -all striving for potential fractional increases in mpg.
Until I am shown differently, I am convinced that use of 0W20 is risking long-term engine wear protection.
Certainly, the cold temperature qualities of the the 0Wxx is no doubt a very good thing . On "cold start" the less viscous oil should reach the critical lubricated parts faster, and certainly have much better lubricating qualities than an oil that is way too thick. And granted, it is common knowledge that the majority of engine wear occurs at startup. But the actual wear protection value due to the very low viscosity value of a 20 weight oil when hot,,,, very questionable I'd say.
Maybe more wear hot, but less wear cold will balance out?? I suspect with 0W30 we can have less wear in total.
So, back to my opening question, given the facts before us, would you consider using 0W30 instead of 0W20?
Thanks to everyone reading this !! Looking forward to your comments.