mryeh17

Synthetic is a marketing term everywhere but Germany (where they have a law specifying base oil used) so I would not focus on it.

There are a lot of characteristics of motor oil besides viscosity curve such as pour point and wear prevention.
0W-20 is a relatively new viscosity grade so using a 0W-20 oil with the API donut / ILSAC starburst ensure the oil meets the latest automotive OEM industry specifications. If you feel the need to use a thicker viscosity oil, I would just be sure the oil meets the latest specs currently GF5.

Galactica

Yes.... all good points, but since no one has claimed to be a certified auto engineer, and more specifically; a Lexus engine design engineer, I'm going with the OEM on this one guys. If the OEM says 10K oil change intervals using 0W-20 synthetic oil, then so it is written, so it shall be. I read a lot of stuff just like everyone else on here, and you can discuss for or against this all day long. But I really like this article from Edmunds because it supports sticking with the OEM recommendations http://www.edmunds.com/car-care/stop...-your-oil.html

Im2bz2p345

Mods: Why was this topic moved to the Hybrid Technology subforum? This section is supposed to be hybrid specific questions. Just because the OP mentioned "450h" doesn't mean the topic belongs here. The description of this subforum even states: "Unique topics related to the GS450H model hybrid drivetrain and other features/options found only on the GS450H. Please use the main 4GS forum for discussion about shared components with other fourth generation GS models."

This is a general question because the type/weight of the oil is the same as the on the GS 350 drivetrain (which also uses synthetic 0W-20 oil, hence the large number of responses).

I would kindly request that the topic be moved back to the general 4GS subforum.

~ Im2bz2p345