Don't drive your car with 2 quarts in it. It will be OK to run the 0-W30 with the 0-W40. The oils will mix fine and the 30 weight is good to about 90 degees farenheit.
smartUSA has let it slip that the engines come out of Japan with a non-synthetic engine oil, and is the reason that sUSA has been recently experimenting with an early change to synthetic oil at the U.S. vehicle processing centers (all getting Mobil 1 0W-40). sUSA doesn't want to wait until the first scheduled maintenance at 1yr/10K miles to change to synthetic.... Never figured out if they ship the car with reg. oil or mobil 1.But it didn't look synthetic. ...
Sort of off topic, but the assumption that "we" want to conserve oil may be faulty. As the manufacturers improve engine technology and the oil companies improve their oils to enable longer oil change intervals, old habits die hard - some folks can't let go of the 3K mile oil change, others want to do the "engine flush" thing, etc. Must really confuse the auto and oil company engineers.So if we want to conserve oil,a country that has no oil,ships its cars with old,'basic' oil,so you can get rid of it and conserve oil?
Modern API SM grade fossil oil isn't exactly "'old' oil." It is perfecty acceptable if used within its intended parameters - that its extreme ends of its viscosity range aren't challenged, and that it not used in extended oil change intervals (10K +). Many manufacturers still specify a 7,500 mile interval (in ideal, non-severe service use), and a fossil SM can do that.... why would you ship it with,'old' oil? ...