Originally Posted by BLND1
Toyota specs a wide range of oil viscosities for varying temps in its 1GR-FE (4v DOHC V6 - Tacoma, landcruiser, Hilux, 4Runner, etc...) on the world market. But only one per vehicle type in the US.
CAFE requires US manufacturers provide the oil viscosity used for CAFE testing to be printed in the manual and on the fuel cap. Hence why you tend to see only a single viscosity on a majority of newer cars sold in the US.
It's ridiculous that an engine that specs 5w30, 10w30, 15w40, and 20w50 in Australia ONLY specs 5w30 in the US.
Sure there might be differences but I'll bet the ones that matter, I.e. bearing clearances, etc. are the same.
If your usage tends towards "severe" or your annual average temps are high, I don't see an issue with a heavier oil.
Let's not pretend like 0w20 is anything but a CAFE required crutch to eek another 1/2MPG overall for manufacturer fleet totals. Manufacturers are building many of the same engines for other markets and recommending thicker oils.
A little common sense goes a long way.
Very well said sir; better than I could have said it.
Hopefully you won't mind if I steal a piece of that post for my signature… With full credit to you of course