NHTSA Complaint #11555646 — 2020 HYUNDAI PALISADE

Problems started about 1.5yrs ago - car would make horrible noises from the engine, knocking sounds, lost some electric/AV systems. Brought to local dealership, had a bunch of codes; dealer said issue with t-stat sensor. No issues for another 3k miles, knocking sounds again. Mentioned to service advisor during oil change, couldn't recreate. Same problem every 3k miles, dealer/service repeatedly couldn't recreate issue/sound. Check engine light comes on, dealer said issue with EZ-Pass interfering with computer, need to pay $150 to reset computer and move EZ-Pass. Continue to take car for oil changes at dealerhip every 3k miles. In May 2023, dealer/service used 0w20 oil instead of 5w30 - apparently dealer/service noticed no oil in car, but didn't tell us, thought different oil weight would help "stretch" oil to next oil change interval (it didn't - burned through all 6.9qts before the end of 3k miles). End of Sept 2023, car sounds horrible again, losing auto stop/start feature, knocking. Husband found YouTube video of similar issues for same car - checked oil dipstick, bone dry. We added 5qts of oil, called Hyundai Corp and dealership, setup for oil change and to start consumption test. Dealer/service overfilled oil (charged for 8qts, car take 6.9, usual charge for 7qts, suddenly charged 8qts?) 1st 1000miles, dealer notes oil 1.5qts low, 2nd 1000 notes 1.4qts low. Dealer says excessive, but need to continue with consumption test. I've taken videos of my dipstick before each consumption test, dipstick shows oil at or below L. No oil lights ever displayed on car dash. Dealer attempted to coverup faulty engine, hoping I'd get past warranty coverage.