2018 Kia Optima: what breaks, and at what mileage
What breaks on the 2018 Kia Optima
On the 2018 Kia Optima, the failure owners report most often is other engine problem, and the reports cluster around 65,000 miles. Across every failure mode on this year, half the dated reports were filed before 45,000 miles. Overall it scores 75 out of 100, severe risk for a 2018.
Severe risk for a 2018 — 129th riskiest of the 251 2018 vehicles we can rate. 334 owner reports; fleet size estimated from this year's own recall paperwork.
The failures owners actually file about
Owners have reported 47 named failure modes on the 2018 Kia Optima, and the three most-reported carry 40% of everything filed.
Other engine problem leads with 69 reports, about 1.9 per 1,000 vehicles and with the middle half of reports between 40k to 107,500 miles.
Excessive oil consumption follows with 43 reports, median 100,000 miles.
Other electrical problem follows with 20 reports, median 45,000 miles.
By system, the reports fall mostly into engine (139), electrical (29) and transmission (24).
At what mileage it happens
115 of the reports on the 2018 Kia Optima came with an odometer reading, and half of those were filed before 45,000 miles.
Cumulatively, 53% by 50,000 miles, 82% by 100,000 miles and 99% by 150,000 miles of the dated reports had been filed.
The busiest stretch is between 10,000 and 20,000 miles, which alone holds 17% of the dated reports.
39% of the dated reports were filed below 36,000 miles, which is early enough that a fair number of these cars were still under a factory warranty when the owner complained.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
Showing the 12 most-reported failure modes of 47. The full list is in the table below.
How reports accumulate
Every report with an odometer reading, cumulative, from 0 to 200,000 miles. A curve that climbs early is a car with early problems, whatever its total.
- Line share of reports filed by that mileage
- Dashed the median reported mileage
How bad it is when it goes
Across the named modes, 12 mention a crash, 13 a fire and 10 an injury. Those are the words owners used in their own complaints, and NHTSA does not verify them, but they are the closest thing in this data to a measure of what a failure actually did.
The average severity weight across every report on this year is 4.38, where a stalled engine or a failed airbag weighs many times more than a rattling trim panel, and a figure this high means the reports are dominated by failures with safety consequences rather than annoyances. The weighting is set out in full on the methodology page.
What the top failures cost to put right, as editorial estimates for an independent US shop rather than figures from NHTSA: other engine problem at $300–$4,000, excessive oil consumption at $900–$6,500, other electrical problem at $250–$2,000 and other powertrain problem at $400–$4,500. Dealer labour, a seized bolt or a part that is no longer made can push any of these past the top of its range.
49% of the reports on this year sit in the engine, transmission, drivetrain or cooling systems — the four where a repair bill is usually four figures.
Every reported failure mode
| Failure mode | System | Reports | With reading | 25th | Median | 75th | Per 1,000 | Typical repair | Severity |
|---|---|---|---|---|---|---|---|---|---|
| Other engine problem | engine | 69 | 29 | 40k | 64k | 107k | 1.9 | $300–$4,000 | High |
| Excessive oil consumption | engine | 43 | 7 | — | 98k | — | 1.2 | $900–$6,500 | High |
| Other electrical problem | electrical | 20 | 6 | — | 44k | — | 0.6 | $250–$2,000 | Moderate |
| Other powertrain problem | transmission | 17 | 5 | — | 31k | — | 0.5 | $400–$4,500 | High |
| Fuel pump failure | fuel | 11 | 4 | — | 68k | — | 0.3 | $600–$2,600 | High |
| Other brake problem | brakes | 11 | 5 | — | 40k | — | 0.3 | $300–$1,800 | High |
| Other lighting problem | lighting | 11 | 2 | — | 33k | — | 0.3 | $120–$1,200 | Moderate |
| Other speed control problem | adas | 10 | 3 | — | 23k | — | 0.3 | $250–$2,000 | Critical |
| Oil leak | engine | 8 | 0 | — | — | — | 0.2 | $250–$2,200 | Moderate |
| Misfire or rough idle | engine | 8 | 3 | — | 68k | — | 0.2 | $250–$1,600 | Moderate |
| ABS module or sensor failure | brakes | 8 | 4 | — | 57k | — | 0.2 | $500–$2,400 | High |
| Other steering problem | steering | 8 | 4 | — | 39k | — | 0.2 | $350–$2,400 | High |
| Airbag failed to deploy in a crash | airbag | 6 | 5 | — | 7k | — | 0.2 | $1,000–$5,000 | Critical |
| Seat belt or retractor failure | airbag | 5 | 2 | — | 52k | — | 0.1 | $200–$900 | High |
| Other fuel system problem | fuel | 5 | 0 | — | — | — | 0.1 | $300–$2,200 | High |
| Head gasket failure | engine | 4 | 0 | — | — | — | 0.1 | $1,400–$4,000 | Critical |
| Alternator or charging system failure | electrical | 4 | 3 | — | 37k | — | 0.1 | $450–$1,600 | High |
| Headlight failure or clouding | lighting | 4 | 0 | — | — | — | 0.1 | $150–$1,800 | Moderate |
| Software fault or failed update | software | 4 | 2 | — | 37k | — | 0.1 | $0–$600 | Moderate |
| Other driver assistance problem | adas | 4 | 4 | — | 6k | — | 0.1 | $250–$1,800 | High |
| No-start or intermittent start failure | engine | 3 | 2 | — | 19k | — | 0.1 | $200–$1,800 | Moderate |
| Complete transmission failure | transmission | 3 | 1 | — | 4k | — | 0.1 | $2,800–$8,000 | Critical |
| Sunroof failure or glass breakage | body | 3 | 2 | — | 21k | — | 0.1 | $700–$4,500 | High |
| Tail light, brake light or signal failure | lighting | 3 | 1 | — | 9k | — | 0.1 | $100–$900 | Moderate |
| Engine bay fire | engine | 2 | 1 | — | 22k | — | 0.1 | $4,000–$20,000 | Critical |
| Transmission slipping | transmission | 2 | 0 | — | — | — | 0.1 | $1,200–$5,500 | High |
| Wiring harness or short circuit | electrical | 2 | 1 | — | 15k | — | 0.1 | $400–$3,500 | High |
| Ignition switch, key fob or immobilizer failure | electrical | 2 | 0 | — | — | — | 0.1 | $250–$1,500 | High |
| Catalytic converter failure | emissions | 2 | 0 | — | — | — | 0.1 | $900–$3,500 | Moderate |
| Other wheel or tire problem | wheels | 2 | 2 | — | 14k | — | 0.1 | $200–$1,500 | High |
| Other body or interior problem | body | 2 | 1 | — | 15k | — | 0.1 | $200–$2,000 | Moderate |
| Complete engine failure or seizure | engine | 1 | 0 | — | — | — | 0.0 | $4,500–$12,000 | Critical |
| Engine knock or bearing noise | engine | 1 | 0 | — | — | — | 0.0 | $2,500–$9,000 | High |
| Overheating | cooling | 1 | 1 | — | 77k | — | 0.0 | $400–$3,500 | High |
| Harsh or jerky shifting | transmission | 1 | 0 | — | — | — | 0.0 | $600–$4,000 | Moderate |
| Torque converter failure | transmission | 1 | 1 | — | 112k | — | 0.0 | $1,100–$3,200 | High |
| CV axle or driveshaft failure | drivetrain | 1 | 1 | — | 63k | — | 0.0 | $450–$2,200 | High |
| Control module (ECM/PCM/BCM) failure | electrical | 1 | 0 | — | — | — | 0.0 | $700–$3,000 | High |
| Master cylinder or brake booster failure | brakes | 1 | 1 | — | 146k | — | 0.0 | $450–$2,200 | Critical |
| Airbag warning light or occupant sensor fault | airbag | 1 | 0 | — | — | — | 0.0 | $300–$1,600 | High |
| Lane keep or steering assist fault | adas | 1 | 0 | — | — | — | 0.0 | $200–$1,600 | High |
| Blind spot monitor failure | adas | 1 | 0 | — | — | — | 0.0 | $250–$1,300 | Moderate |
| Control arm, ball joint or bushing failure | suspension | 1 | 0 | — | — | — | 0.0 | $400–$2,200 | High |
| Alignment fault and uneven tire wear | suspension | 1 | 0 | — | — | — | 0.0 | $150–$1,200 | Moderate |
| Rust or structural corrosion | body | 1 | 0 | — | — | — | 0.0 | $500–$6,000 | High |
| Liftgate, tailgate or trunk failure | body | 1 | 0 | — | — | — | 0.0 | $250–$1,500 | Moderate |
| Other visibility problem | glass | 1 | 1 | — | 125k | — | 0.0 | $150–$1,400 | Moderate |
| Unclassified problem | other | 32 | 11 | 24k | 33k | 49k | 0.9 | — | Moderate |
Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound. Repair costs are typical independent-shop ranges for the failure, not figures from these reports.
How often, against how many were built
Scaled by an estimate of how many of these cars exist, the 2018 Kia Optima draws about 9.4 per 1,000 vehicles, which puts it in the 90th percentile of complaint rates among 2018 vehicles we can rate.
That denominator is the weakest number on the page and it is fair to say so plainly. Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound.
The working figure is 35,492 vehicles. If the true number is twice that, every rate on this page is half what it says; the ranking against other 2018 vehicles, which is what the risk score uses, is far more robust than the rate itself.
Recalls on the 2018 model year
NHTSA has issued 2 recall campaigns covering the 2018 Kia Optima, affecting an estimated 36,347 vehicles. A recall is a different kind of evidence from a complaint: it is the regulator and the manufacturer agreeing that something has to be fixed, and the fix is free for as long as the car exists.
The campaigns cover latches/locks/linkages:trunk lid:latch and hybrid propulsion system. Whether the work was actually done on the car in front of you is a question only the VIN can answer, and the manufacturer or NHTSA will answer it free.
Recalls also distort complaint counts. Publicity about a campaign reminds owners that complaining is possible, so reports for a recalled component often spike after the recall rather than before it.
LATCHES/LOCKS/LINKAGES:TRUNK LID:LATCH
319,436 vehicles 2023-08-24- Defect
- Kia America, Inc. (Kia) is recalling certain 2016-2017 Rio, 2016-2018 Optima, 2017-2018 Optima Hybrid and Optima Plug-in Hybrid vehicles. The trunk latch base may crack, preventing the opening of the trunk from the inside. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 401, "Internal Trunk Release."
- Consequence
- A person inside the trunk compartment may become trapped, increasing their risk of injury.
- Remedy
- Dealers will replace the trunk latch base subassembly, free of charge. Owner notification letters were mailed October 19, 2023. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC278.
HYBRID PROPULSION SYSTEM
1,710 vehicles 2018-03-08- Defect
- Kia Motors America (Kia) is recalling certain 2017-2018 Kia Optima hybrid vehicles. These vehicles are equipped with a Voltage Protection Device (VPD), designed to protect the high voltage battery module, that may activate inadvertently.
- Consequence
- If the VPD activates while the vehicle is being operated in Electric Vehicle (EV) mode, there may be a loss of power, increasing the risk of a crash.
- Remedy
- Kia will notify owners, and dealers will remove the VPD switch and install two newly designed Battery Management Systems (BMS) that contain Overvoltage Protection Devices (OPDs), free of charge. The recall is expected to begin May 2018. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC162.
Recall work is free at a franchised dealer regardless of the car's age. Check the VIN at nhtsa.gov/recalls before assuming it was done.
How it ranks in the 2018 field
The score at the top of the page, placed among its peers. The zones are the same thresholds the scorer applies, read out of the scorer itself, so the picture and the band word cannot disagree.
Scores are ranked within the model year, never across years, because an older car has had longer to accumulate reports.
- Left fewer and less serious reports
- Right more, or worse
- Marker this vehicle
Better and worse years of the same car
Severe risk for a 2018 — 129th riskiest of the 251 2018 vehicles we can rate. Every score on this site is a rank inside its own model year, which is what makes a 2004 and a 2019 comparable at all.
Across the 20 model years of this car that carry enough reports to score, 2005 comes out best at 57 and 2019 worst at 80, with 2018 itself at 75.
If the model year is negotiable, 2005, 2003, 2007, 2006, 2004, 2002, 2010, 2009, 2001 and 2008 score lower than 2018 by a margin worth acting on. Same body, same engines, different luck — usually a supplier change or a mid-cycle fix, which the complaint data can show but never explain.
Within the 2017–2020 generation specifically, 2020 is the strongest year at 73 and 2019 the weakest at 80.
Scores compare each year against other cars of the same model year, so a low number on an older car is a real result and not an artefact of age.
Shorter is better. Years with too few reports to score are shown without a bar rather than as a zero, because no data is not good news.
Within the 2017-2020 generation, 2020 Kia Optima scores best at 73 and 2019 Kia Optima worst at 80.
Where to spend the inspection money
The mileages below are where the first quarter of reports for each mode had already been filed, which makes them the point at which a fault is worth looking for rather than the point at which it happens: other engine problem from about 40k.
On a 2018 Kia Optima with more miles than that on it, the useful question to put to a seller or a mechanic is whether other engine problem has been dealt with, and if so with what parts and at whose expense. A car that has already had the repair is in a different position from one that has not.
None of this is a diagnosis. It is a list of what other owners of the same model year reported, ordered by when they reported it, which is a good place to point an inspection and a poor place to stop.
Where these figures stop being useful
334 owner reports; fleet size estimated from this year's own recall paperwork. Every count on this page is therefore a floor: it is the number of owners who went to the trouble of filing with a federal agency, which is a small and self-selected fraction of the owners who had the fault.
Of those 334 reports, 115 carried an odometer reading, so the mileages here describe 34% of the sample rather than all of it. Owners also round: readings pile up on multiples of ten thousand, which is why this site publishes "about 90,000 miles" and not "91,438".
Named failure modes come from matching phrases in the complaint text, so a badly worded complaint can land in the wrong bucket. The effect washes out across hundreds of reports and does not wash out across five.
And nothing here predicts what one car will do. These are other people's complaints, filed years apart, on cars maintained by strangers. Read the page as a map of where this model year has previously gone wrong, then have the specific car in front of you inspected.
Questions this page answers
What are the most common problems with the 2018 Kia Optima?
The most-reported failures are other engine problem (69 reports, median 65,000 miles), excessive oil consumption (43 reports, median 100,000 miles) and other electrical problem (20 reports, median 45,000 miles). Counts come from owner complaints filed with NHTSA, which are voluntary, so they show what owners bothered to report rather than every fault that occurred.
At what mileage do 2018 Kia Optima problems start?
Other engine problem is the earliest failure mode to show up, with a median reported mileage of 65,000 miles and a quarter of reports before 40,000 miles. Across all failure modes on this year, the median report sits at 45,000 miles.
Is the 2018 Kia Optima reliable?
It scores 75 out of 100 on our risk index, which is severe — 129th riskiest of the 251 2018 vehicles we can rate. The score is a comparison against other 2018 vehicles, not a prediction about any individual car, and it is built from complaint rates, severity and how early failures appear.
Which year of the Kia Optima is best?
Within the 2017–2020 generation, 2020 scores best at 73 out of 100 and 2019 worst at 80. Same body, same engines, different luck.
Where this comes from. Every figure above is computed from NHTSA owner complaints and recall records for this exact make, model and year. Complaints are voluntary and self-selected, so treat counts as a floor. The methodology page writes out each formula, and the same numbers are available as JSON.
What breaks at my mileage Compare with another car
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