My 2017 Elantra SE with 100k warranty is just approaching 30k miles. I have been doing the 3,750 mile/6-month oil changes which meant two a year. My work schedule changed and am driving more. Would like to do 5k or 6 month oil changes. Oil I will be using is mostly 5w-20 Pennzoil Ultra Plantinum or 5w-30 Pennzoil Platinum in summer. I noticed the 2021 Elantra recommendation is 0w-20 at 5k intervals for severe service. I am using the most recent version of OEM filter. If I extend my oil change by miles a little what rights do I have if something goes wrong with my car? I hear a lot of scary stories of Hyundai denying warranty. At this point saving warranty is more import than saving oil changes. On the other hand I know the oils I will use will have no problem with a 5k interval. I noticed dealership is posting on their website oil change should be done about every 7,500 to 10,000k. That is a lot different than the 3,750 they recommended when I bought my car.