Virtually all Toyotas recommend 0W-20 in the U.S. market owners manual. Yet, the official service data sheet, factory service manual, and owners manual outside of the U.S. market recommends anything but 0W-20.
I've come to the conclusion that 0W-20 is only recommended so that they can meet the latest CAFE standards and do NOT provide the best protection for your engine. In Texas climate, 15W-40 should be used most of the year. You can use 5W-30 or 10W-30 if you want better fuel economy or if you expect temperatures to drop below 10 degF.
The 2015 Toyota Highlander for example,
U.S. market owners manual:
![](https://i.imgur.com/OHynv5l.png)
However, the official service data sheet:
![](https://i.imgur.com/cBvAi2k.png)
Factory service manual:
![](https://i.imgur.com/SvJneub.png)
Australian owners manual:
![](https://i.imgur.com/eB4H1ov.png)
I've come to the conclusion that 0W-20 is only recommended so that they can meet the latest CAFE standards and do NOT provide the best protection for your engine. In Texas climate, 15W-40 should be used most of the year. You can use 5W-30 or 10W-30 if you want better fuel economy or if you expect temperatures to drop below 10 degF.
The 2015 Toyota Highlander for example,
U.S. market owners manual:
![](https://i.imgur.com/OHynv5l.png)
However, the official service data sheet:
![](https://i.imgur.com/cBvAi2k.png)
Factory service manual:
![](https://i.imgur.com/SvJneub.png)
Australian owners manual:
![](https://i.imgur.com/eB4H1ov.png)
![](https://i.imgur.com/JtzqRWH.png)