Yesterday I went on a hunt to see if I could find any of the discontinued Honda Green Oil, which is what Honda recommended and was putting into Insights, HCH's and CR-Z's in Japan. I remembered reading about it a few years ago, that it doesn't have an SAE rating but was probably thinner than 0w16, definitely a lot thinner than 0w20, but it seems it's basically all gone at this point. One source said after Green Oil was discontinued, Honda was recommending the use of Castrol Edge, and that it was thinner than most other 0w20's.
A look on
Amazon showed Ravenol sells a 0w16, though it's pretty expensive at ~$40 for 4 liters, as compared with ~$25 for 5 quarts of Mobile one 0w20. However, I live in a cold climate (winters down to -40 sometimes), and I'm considering trying it.
This was a good read:
http://www.ravenol.de/fileadmin/cont..._0W-16__en.pdf
Some further googling revealed Honda has an oil called "Ultra NEXT" in Japan which is recommended for their Earth Dreams engines. It's apparently equivalent to something like an ~SAE8, but has no SAE rating on it either.
http://www.fitfreak.net/forums/3rd-g...800-miles.html
Anyone know where I might find some Ultra NEXT? Or, does anyone have any experience with Ravenol's 0w16, especially in colder climates?