More specifically a Kia '07 3.8L (timing chain) V-6
I have a few opinions on the 2007 Kia/Hyundai Lambda 3.8 engine which might relate to your question, but only regarding that engine, and not the 2010 unit. They are just opinions, so I don't intend to flame anyones ride or anything, just share some info.
Firstly, and in summary, I consider the 3.8 Lambda to be tough on its engine lube oil. It has a generous output, and has some mechanical components which will shear, sludge, and cook oil if left too long.
Also, as you might know, the timing chain tensioners on that engine are its Achilles heel. The 3.8 Lambda engine is smooth, powerful, and has truly excellent driveability, but the original (and often defective) chain tensioners can fail completely, causing slack chains to eat the guides and case, then throw off the cam gears resulting in destructive failure of the engine. I have seen it happen. Rattling at startup, followed by increasingly extended chain knocking means the grim reaper has come for the engine, and it must be fixed immediately.
Given that the updated chain tensioners are in place, the early 3.8 will run great with 5w-30 and 10w-30, the 10w-30 even listed by the mfg as an option. I don't like the 5w-20 in this engine at all, although severe cold might warrant it.
Also absolutely critical is the strict utilization of genuine OEM filters. If, for instance, the VIN calls for filtration kit #26320 3C100, then I strongly suggest its use. Installation of the filter post o-ring, the cap o-ring, the post into the housing, and cap to the housing should be done with precision. The Assenmacher Specialty Tools HY 8815 Oil Filter Wrench is excellent for the task.
General notes:
This engine will often leak at the timing cover, oil pan, etc. due to much RTV sealing.
Surge tank (intake plenum) must come off to do spark plugs at 100,000 mi.
VVT engine with the concommitant oil valving, combined with the timing chains and some internal hot spots means it demands quality, clean motor oil. Sludge will not be tolerated by this unit. The VVT system in this engine is another reason to use OEM filtration, as aftermarket out-of-spec oil flow rates have impaired its function. The oil filter here is not a "equivalent fit" brain dead spin-on situation.
TPS can go bad, so if your auto shifts weird, don't suspect it without confirming the updated TPS is in place.
Do not neglect coolant changes.
Guzzles fuel, but this engine is great fun to drive!