What does the owner’s manual say? Often there’s an option.
Manufacturers are using lighter oil to help make the extreme gas mileage requirements dictated by the EPA. But there may be an option to go up one weight, as you’re proposing. I would definitely read the fine print in the manual. And if running a quality full synthetic oil, might be tempted to go up anyway after the warranty period.
It’s interesting, in the non-turbo version of my car, 0W-20 is recommended, while 0W-30 is the recommended weight in the turbo version. The engine displacement is the same, and I bet they are very, very similar.
My car, a 2000 Chevrolet Cavalier Z24 manual says 10W30, but a factory sticker in the engine compartment says 5W30.
Now what?
“It’s interesting, in the non-turbo version of my car, 0W-20 is recommended, while 0W-30 is the recommended weight in the turbo version.”
The oil runs at a hotter temp in the Turbo versions and gets thinner. The turbo heats the oil more than it regularly would because oil flow is how they cool the turbo bearings. Same heat issue is true in the desert southwest with extremely hot temps.
So your example says it all. Extreme heat (severe duty) conditions actually do require a little heavier oil. Such as turbo models and very hot environmental conditions. I don’t care what the manufacturer says...