Other engine problem on the 2018 Hyundai Sonata
2 crashes 5 fires 1 injury 8 of the 85 reports for this failure mention a crash, a fire, an injury or a death. Those are the owner's words on the complaint form, not a verified finding, and one report can mention more than one.
When other engine problem gets reported
Owners of the 2018 Hyundai Sonata report other engine problem at a median of 42,500 miles. A quarter of the reports come in before 7,500 miles and a quarter after 72,500 miles, from 33 reports that carried an odometer reading.
A part like this is normally expected to survive 95,000 miles. It is the 1st most-reported problem on this model year.
The mileage distribution
The reported range runs from 2,500 miles at the tenth percentile to 117,500 miles at the ninetieth, a spread of 114,985 miles across the middle 80% of reports.
A spread this wide points at use rather than design. Towing, climate, service history and city mileage all move a failure like this, so the median is a weak guide to any individual car.
45% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 3,280 miles | 7,500 miles | 41,400 miles | 72,000 miles | 118,265 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Of these reports, 2 a crash, 5 a fire and 1 an injury are mentioned. Owners write their own complaints and the agency does not verify them, so read this as what the reports say happened rather than as a confirmed count.
Putting it right typically runs $300–$4,000 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 26 model years of this car. It shows up earliest on the 2023, at a median of 100 miles, and latest on the 2008 at 115,000 miles.
By volume the 2011 carries the most reports, with 596; the 2018 has 85. A mode that appears across most years of a model is usually a design choice rather than a bad batch.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
Purchased new 2018 sonata sel model in california. While driving, the transmission starts to hard downshift when the brake is applied. I found out that this hard downshifting and jolting/thumping of engine and transmission only occurs when coming to a stop at speeds between 10 to 15mph. It can be described as follows, after the brake pedal has been gently applied and lightly released but then the car itself applied its brake again. It terrifies the driver's driving conditions, mentally and physically.
Also reported on the 2018 Hyundai Sonata
Excessive oil consumption
Other electrical problem
No-start or intermittent start failure
Wiring harness or short circuit
Other powertrain problem
Other body or interior problem
How far this goes
Complaints are voluntary, so 85 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does other engine problem happen on the 2018 Hyundai Sonata?
Across 33 owner reports that included an odometer reading, half were filed by 42,500 miles. A quarter were filed before 7,500 miles and a quarter after 72,500 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is other engine problem on the 2018 Hyundai Sonata?
85 reports have been filed with NHTSA, about 2.4 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed