So Green Oil is more like -5W20 than 0W16...
I can confirm that Green Oil does improve cold start economy.
Winter 2014-15 was on Green Oil and showed less of a FE dip than the very soft 2013-14 winter on 'previous batch' which was supposed and explained to be 0W20 but showed up on the bill as 5W30...
Then last winter on regular 0W20 was good too, while that winter was just 'soft'.
My FE graph october 2012 to now:
(Worst FE in winter 14/15 was a spirited long drive under high wind and rain.
Worst FE's in winter 15/16 were all service and recall related)
Green Oil was definitely better than Unknown Type, and probably better than 0W20.
I'm useless...
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.