I'm going to bring this thread back up because... I like making people question their choices in life. No not really, honestly I write a lot of things. Then re read them and delete them, because I get tired of saying the same things over and over. But I tried to write this one as not a what you should do, but what i'm doing.
If you look in the Toyota Owners manual under oil requirements it says (at least in a 2011):
"The 20 in 0W-20 indicates the oil viscosity when the oil is at its operating temperature. An oil with a higher viscosity may be better suited if the vehicle is operated at high speeds, or under extreme load conditions."
High speeds, as in ground speed, doesn't mean anything to the engine, it's high RPMs. And extreme load means, high engine load.
So I have a 200 with a lift, heavy/high drag off road tires, a high clearance front bumper to let a ton of aerodynamic drag happen, then 4.88 gears, so I wanted to start thinking about this.
Then I looked at how I used me 200. For me personally, it is not a daily, cold starts are limited, it tackles highway speeds with heavy load, and low speed off roading. Then it lives in the south, with limited winter driving.
I have opened this motor up twice now, and I recently opened up my brothers 2017 Tacoma with 50k miles on it, that also uses Toyota 0w-20. Both are clean, very clean. TGMO 0w-20 is a very good oil, and the very high moly it has over it's Mobil 1 counterpart, in my opinion, very nice for a timing chain. But... I'm not really impressed with the wear I see on the cams. Compare that to my Toyota 4.0L that ran 0w-30 for 150k and is still going strong, I'm questioning 20 weight for heavily modified, heavy stressed motors. But again, in a normal use, stock 200, I'd rock TGMO for 500,000k miles.
For a normal 200, even on with a small lift and some all terrains... 0w-20. For someone that daily drives, so cold starts are the real wear factor... 0w-20. For this situation I'm in, combined with Toyota even saying that basically 20 weight is best for most, but not all users, I'm exploring alternatives.
Amsoil SS 0w-30 is in the motor right now with 1,500 miles on it, comparing Amsoil SS 0w-20 with only 3,000 miles, oil pressure: same, temperature: same (remember our 5.7 has a oil cooler). Cam tick is much quieter, and that's the only thing I have detected that's different for now. Give me another 100k of miles, and we will see.
To bring back that other countries without CAFE are recommending 30 weight oils, with some Lexus engine that
@bjowett mentioned that has the same clearances as our engine that uses 30 weight. I'm starting to really think about this.
But again, cold starts are where the real wear occurs for normal users. Also, the "0" in 0w-20, 0w-30, and 0w-40 are absolutely not even close to the same Kinematic viscosity at @40c (i.e. how to flows when cold starting). Even more fun of an example, Amsoil SS 0w-30 is thicker at 40c than Pennzoil Platinum HM 5w-30.
So don't just look at the label and think you can compare it to anything. TGMO 0w-20, solid option, will never deny it. But if there's one thing I know about oil, there is no "best oil."