I think there is an interview where someone asked Clapton, How does it feel to be the best guitarist around and he said he didn't know, they would have to ask Prince.
Use what the manufacturer recommends, you can jump up a grade, but I would never go thinner. You could use 0w20 in a motor that calls for 5w20, but I would not go down to 0w8, 0w12 or 0w16. Older, high mileage engines if using oil, I would not be afraid to 0 or 5W30.
I talk to a blender, they told me E10 in the winter, can legally have up to 12.4 percent ethanol along with 2 percent Butane for winter blends. So I always say E10 is like E15 in the winter. They have the technology to blend it right to 12.4 percent and still label it 10 percent.
Mine rattles once in a while, some oil filters seem to affect it more than others also. If it was me, I would use 5w30 and change it again in 1500 miles. I'm sure that the iron numbers will come down. Jeep is a great vehicle, has Jeep had problems but they are no worse than any other vehicle and...
They need to get off the ship as soon as possible, that's how they will catch it, not from human to human. I always say, if you want to get sick, go on a cruise. Media always plays with people minds.