I use only oem hyundai/kia filters. We've had the car for 2 years and it's been like this the whole time. Just wanting to try and eliminate it. It's not a gdi engine. It's just a 2.0l 4 cyl. No direct injection. Will 5w30 help at all? I don't want to run 10w30 as it gets cold here in ny in the winter and in the manual it says to only use 10w30 if it's above 30 degrees Fahrenheit and it's not in ny during the winter.
Not sure what the problem is, but I would try an 0w30 in the winter or the 10w30 in the summer AND keep the next oil change interval short to help clean up the block.
OEM, Bosch or Mann (Made in Germany only) oil filter, OEM of Bosch (Made in Germany only) fuel filter.
Also when you do a full service, try using a good major brand fuel additive. I use Liqui Moly SpeedTec, but there are lots of cheaper equivalents.
VVT bearing or retaining pin wear can both cause rattles and if you don't want to fix it (Best done when the cam belt service is done), then I would use an idle only flush (Liqui Moly or Amsoil) and then try Ceratec to see if it reduces the rattle, in addition to moving up from the 20's to the 30's.
Don't use a flush if you have any oil leaks, just short OCI's.