Originally Posted By: willbur
Thank you Spasm3 for your valuable comment. However, I don't think Hyundai just lists multiple oil choices and asks you to pick the one you like. These oils are spec'd for the conditions you drive under and the applicable oil is then used. Personally, I would trust Hyundai and their oil recommendations over internet oil experts. This is way overthought. Just saying...
Perhaps seeing the page from the manual will help.
http://www.hyundaisonatamanual.com/sonata-296-recommended_lubricants_and_capacities.html
Quoting the manual here
"Engine oil viscosity (thickness) has an effect on fuel economy and cold weather operating (engine start and engine oil flowability). Lower viscosity engine oils can provide better fuel economy and cold weather performance,
however, higher viscosity engine oils are required for satisfactory lubrication in hot weather. Using oils of any viscosity other than those recommended could result in engine damage."
"*1. For better fuel economy, it is recommended to use the engine oil of a viscosity grade SAE 5W-20 (API SM / ILSAC GF-4). However, if the engine oil is not available in your country, select the proper engine oil using the engine oil viscosity chart."
Here is a chart for a 2014 sonata, i don't have a 2017 chart but its in the link above.
So in summary Hyundai lists 5w20, 5w30, and 10w30 that you can chose to run as you see fit.