2018 Hyundai Sonata fuel/propulsion system problems
30 owner complaints filed with NHTSA name the fuel/propulsion system on the 2018 Hyundai Sonata — 8% of all complaints for this model year.
What owners report
“Engine blown out malfunction took two dealer Hyundai Folsom Lake stated rings are bad sludge buildup in engine and stayed at Hyundai motor America denied engine replacement due to knowledge under Theta two engine extended warranty settlement of 150,000 MI 15 years I'm still within warranty but are…”
filed May 12, 2026
“I am submitting this complaint to report a serious and ongoing safety defect involving the engine of my 2018 Hyundai Sonata Sport equipped with the 2.4L Theta II engine. The vehicle has been officially tested and documented by Hyundai as consuming more than two (2) quarts of engine oil per 1,000…”
filed May 6, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Fuel/propulsion System problems in other Sonata years
| Year | Reports | Share |
|---|---|---|
| 2024 Sonata | 1 | 2% |
| 2023 Sonata | 36 | 43% |
| 2022 Sonata | 22 | 24% |
| 2021 Sonata | 18 | 14% |
| 2020 Sonata | 45 | 26% |
| 2019 Sonata | 11 | 7% |
| 2017 Sonata | 33 | 4% |
| 2016 Sonata | 32 | 4% |
| 2015 Sonata | 72 | 6% |
| 2014 Sonata | 49 | 7% |
| 2013 Sonata | 133 | 7% |
| 2012 Sonata | 99 | 6% |
Other reported problem areas on the 2018 Hyundai Sonata
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.