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2018 Kia Optima

Owner reports · Recalls · Investigations

Similar to other model years

Owner complaints for the 2018 Kia Optima do not stand out strongly from the model-year median of 186.5.

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When problems were reported

Mileage at the reported incident

73 reports with mileage · 159 unknown

NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.

What to inspect

Issues worth paying extra attention to based on owner reports.

  • Engine. Review the 131 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Electrical System. Review the 33 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 18 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

10 crash reports10 fire reports7 injury reports

Fuel/propulsion System complaints

13 reports
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Mileage unknown · Mar 18, 2026
Electrical SystemFuel/propulsion SystemUnknown Or Other

I am submitting this complaint regarding ongoing and persistent mechanical issues with my vehicle since the time of purchase. The vehicle has repeatedly shut off unexpectedly, creating a serious safety concern. Initially, I suspected the issue might be related to the battery, and I have replaced the battery twice within the pas…

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I am submitting this complaint regarding ongoing and persistent mechanical issues with my vehicle since the time of purchase. The vehicle has repeatedly shut off unexpectedly, creating a serious safety concern. Initially, I suspected the issue might be related to the battery, and I have replaced the battery twice within the past 4 years. However, the problem has continued. In January, the vehicle began shaking and shutting down again. I took it to a mechanic, who diagnosed the issue as faulty spark plugs and an ignition coil. The diagnostic codes provided were P0303 and P0456, and the recommended repairs were completed. Approximately one month later, the vehicle began shutting off again. I then took it to the dealership, where I was advised that the valve cover gasket needed to be replaced, along with the belts, and that a fuel system cleaning was required. I subsequently had these repairs completed by my mechanic. Less than a week after completing those repairs, the vehicle once again began shutting down. A diagnostic scan then produced code P123300. In addition to these repeated shutdowns, the vehicle consumes an excessive amount of oil, has poor acceleration, and continues to stall unexpectedly both while driving on the road and while idling, such as in a drive thru. These recurring issues have made the vehicle unreliable and unsafe. I am concerned about the risk of the vehicle shutting off while in motion, which could lead to a dangerous situation. I am requesting that this matter be reviewed for potential defects or safety-related concerns.

NHTSA ODI #11725280

Mileage unknown · Nov 5, 2025
Electrical SystemEngineFuel/propulsion System

On August 26, 2025, I brought my 2018 Kia Optima Plug-In Hybrid to an authorized dealer for recall SC218 (engine inspection and KSDS software update). The dealer verbally stated both SC218 and SC278 recalls were completed, and the repair order (RO #XXX) lists them as performed. In September 2025, Kia America emailed me showing …

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On August 26, 2025, I brought my 2018 Kia Optima Plug-In Hybrid to an authorized dealer for recall SC218 (engine inspection and KSDS software update). The dealer verbally stated both SC218 and SC278 recalls were completed, and the repair order (RO #XXX) lists them as performed. In September 2025, Kia America emailed me showing recall SC218 still open, and a warranty coverage report dated September 26, 2025, again listed SC218 as unclosed. On November 4, 2025, NHTSA’s official VIN lookup confirmed the recall remains “Incomplete.” On October 21, 2025, Kia America emailed me under Case #XXX stating that SC218 was “confirmed completed” and that the dealer performed a software update to the ECU, referencing RO #XXX. However, NHTSA’s database still lists recall SC218 as incomplete. This contradiction between Kia America’s internal record, the dealer’s invoice, and the federal NHTSA database raises a serious safety concern that the recall inspection or software update was never actually performed or was never reported correctly. I have requested written proof and diagnostic data (Battery SOH report) multiple times but have not received them. If accurate, this means I was led to believe my vehicle’s engine-safety recall had been repaired when federal records still list it as open. I am requesting NHTSA to review this reporting discrepancy, ensure Kia America and the dealer produce verifiable proof of completion, and confirm that the federal record is corrected. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11697664

Mileage unknown · Jul 18, 2025
EngineFuel/propulsion System

My 2018 Kia Optima LX began using excessive oil (>3 quarts/1000 miles) just over 100K miles. I researched and found that the Theta II engine in my car is known for this. When I took my car to dealership (Stokes Hodges Kia, North Augusta, SC), with the check engine light on, they told me me plugs were fouled (they were just repla…

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My 2018 Kia Optima LX began using excessive oil (>3 quarts/1000 miles) just over 100K miles. I researched and found that the Theta II engine in my car is known for this. When I took my car to dealership (Stokes Hodges Kia, North Augusta, SC), with the check engine light on, they told me me plugs were fouled (they were just replaced 1 yr prior), cylinder 3 misfiring, and that I needed to pay a few thousand dollars to have repaired. When I asked them to guarantee the soaking process they recommended, they responded that they couldn't, that it "only worked 80% of the time." I have the KSDS download since 2019 and asked them to follow the guidelines of their TSB ENG 222 for the class action lawsuit and start a 1000 mile oil consumption test. they refused, basically telling me the only way to get a new engine from Kia, since my car is over 100K miles, is to drive it until the engine seizes. I expressed my fear for personal safety, but they wouldn't help me. I am original owner and have all services, etc documented. I called Kia customer affairs, then was told only local dealership could help. they stuck me in a loop between them without helping. Please help me.

NHTSA ODI #11674425

Mileage unknown · Jul 10, 2025
Fuel/propulsion SystemService BrakesVehicle Speed Control

Purchased car about 4 months ago, before warranty ran out, the shop looked at it told me it was fine, it wouldn't accelerate. Few weeks later same issue but all my oil was gone, they found 11 things wrong with the vehicle, told me warranty wouldn't take care of it unless the engine blow up. The salesman Scottie Mitchell told me…

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Purchased car about 4 months ago, before warranty ran out, the shop looked at it told me it was fine, it wouldn't accelerate. Few weeks later same issue but all my oil was gone, they found 11 things wrong with the vehicle, told me warranty wouldn't take care of it unless the engine blow up. The salesman Scottie Mitchell told me check Kia for recalls, called Kia 3 recalls, they were trying to finance another car higher, back wanted to know why the dealership didn't know about recalls, Kia place did call a Robert. One of the owners did know about recalls, why dealership didn't pass them on. They trying to sell me a higher vehicle to keep cover the cost of the one I got 1st

NHTSA ODI #11672508

Mileage unknown · Nov 1, 2023
Fuel/propulsion System

THE FUEL PUMP HAS AN ACTIVE RECALL. TOOK ITIN TO DEALER AND WE ARE BEING ADVISED KIA WILL NOT COVER THE COST. THEY HAVE AN ARTICLE OUT THAT CLEARLY STATES THEY WILL COVER THE COSTS. THE CAR WREAKS OF THE SMELL OF GAS AND WE ARE SCARED IT WILL CATCH FIRE.

NHTSA ODI #11553112

Mileage unknown · Aug 25, 2023
Fuel/propulsion System

Leaking gas at the firewall when running.

NHTSA ODI #11540760

Mileage unknown · Aug 19, 2023
EngineFuel/propulsion System

purchased my car in june of 2019. Ive scheduled regular oil changes and maintenance until june of 2020 where the engine light began to flicker and the car would shake. I took to Koons Kia owings mills md and it was repaired. Next year same thing. Oil compression issues all year round where i have to keep putting oil in. No…

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purchased my car in june of 2019. Ive scheduled regular oil changes and maintenance until june of 2020 where the engine light began to flicker and the car would shake. I took to Koons Kia owings mills md and it was repaired. Next year same thing. Oil compression issues all year round where i have to keep putting oil in. Now my car starts and shakes violently. the kia service modurator on the car indicated there were an engine issue. I cannot keep dishing money into this car with so many recalls (current fuel pump recall and anti theft issue) is also included. Please help

NHTSA ODI #11539542

Mileage unknown · Aug 8, 2023
EngineFuel/propulsion SystemPower Train

I'm reporting these issue pertaining to the engine within the first 3 weeks AFTER the engine replacement recall was serviced and completed. The vehicle was exhibiting the same defects and major health and safety hazards as before the new engine. Intermittent engine failure, even worse, while i was trying entering the hwy at spee…

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I'm reporting these issue pertaining to the engine within the first 3 weeks AFTER the engine replacement recall was serviced and completed. The vehicle was exhibiting the same defects and major health and safety hazards as before the new engine. Intermittent engine failure, even worse, while i was trying entering the hwy at speeds of 45-50 miles it jerked very violently and loss total power while vehicles were behind me nearly rear ended. Prior to this I reached out multiple times to have it serviced at again. The original service department didn't respond, so I called other service departments and was told it needed to be serviced by the original dealership/service department that replaced the engine. I had the vehicle in normal working conditions a few days before it began exhibiting the same problems as before the engine replacement. It was in operable condition but still stalling and refusing to crank unless primed, until it ultimately just would not crank at all and is back in the same condition it was before the new engine but it is not locked up currently. The time frame and Milage between first experiencing the issues to now, March 2023-64745 Started shuddering, loss of power while driving, but would crank right back up without issues. Happened a few times, charged up battery thinking is was am electrical issue. April 2023 More frequently the issues occurred, still same severity levels. May 2023 Began happening every time at an idle, whether I was at a fast food in drive through placing an order, or to wash the car. Every time at an idle this would happen, and would take a few times of trying to start the vehicle and after about 5 seconds of cranking it would catch and work. I began placing the vehicle in neutral while at idle and it would assist In the stalling out sometimes. After a few days of this it refused to crank due to the engine locking up. Milage at this time was 68048. Aug 2023-New engine, drove about 2k miles-70207 current

NHTSA ODI #11537251

68,000 miles · Jun 6, 2023
EngineFuel/propulsion SystemSteering

High injector fuel pump top engine mount went out at 68000 miles. It caused the vehicle to stall and lose power and basically cut the car off while driving.

NHTSA ODI #11525549

Mileage unknown · May 31, 2023
EngineFuel/propulsion SystemVehicle Speed Control

-Knock Sensor Detection System - ECU Logic Improvement - I Was driving with my infant son in the backseat. I was going 70 mph when my car started rapidly losing speed. This happened again with just myself after receiving the car from mechanic. There was heavy traffic and I had to swerve to avoid being hit by an 18-wheeler. - I…

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-Knock Sensor Detection System - ECU Logic Improvement - I Was driving with my infant son in the backseat. I was going 70 mph when my car started rapidly losing speed. This happened again with just myself after receiving the car from mechanic. There was heavy traffic and I had to swerve to avoid being hit by an 18-wheeler. - I can see on the website where I received the car from, there is a recall for my exact make and model with the same code but they say there is no recall for my specific car. - The check engine light started flashing and Kia Systems starts talking.

NHTSA ODI #11524617

Official recalls

2

23V594000 · Latches/locks/linkages:trunk Lid:latch

Aug 24, 2023

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 & remedy

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.

18V161000 · Hybrid Propulsion System

Mar 8, 2018

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 & remedy

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.

Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗

NHTSA investigations

2

DP22003 · Loss Of Motive Power

Opened Sep 12, 2022 · Closed Dec 12, 2023

Status: closed (inferred from source dates) · Engine

The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021. The Petitioners cited examples of complaints indicating that the subject vehicles were experiencing rapid loss of engine oil due to oil drain plug back outs, resulting in loss of motive power and/or catastrophic engine damage. Additional complaints were provided which alleged that the oil drain pans lack sufficient structural integrity and are susceptible to cracking. The petition itself can be reviewed at NHTSA.gov under ODI number 11481745. On September 12, 2022, the Office of Defects Investigation (ODI) opened Defect Petition (DP22-003) to evaluate the Petitioners’ request. The Petitioners have provided additional complaints within four supplemental letters dated January 31, 2023, March 21, 2023, May 23, 2023, and August 4, 2023. ODI’s evaluation included the review and analysis of the complaints and supporting information submitted by the Petitioners, as well as additional complaints submitted directly to NHTSA which referenced either the oil drain plug or a crack in the oil pan. After reviewing the available data, ODI has not identified evidence that would support opening a defect investigation into the oil drain pan assemblies of the subject vehicles. Based on a review of the available information, a loss of motive power resulting from an oil drain plug back out has not occurred between the initial sale of a vehicle and the completion of its first oil change. If during an oil change service, a technician fails to remove the existing drain plug gasket before installing a new gasket, it is likely that a proper seal between the drain plug and the oil pan will not be made. An improper seal between the drain plug and oil pan could lead to the backing out on the drain plug, resulting in the sudden loss of oil while driving. Additionally, the provided examples of oil pan cracks were localized to the immediate vicinity of the oil drain plug and/or appeared to be the result of direct-contact with a tool during servicing.  There is no information to support that a vehicle-based defect exists relating to the oil pan assembly, and instead the documented incidents are related to the failure to follow the proper maintenance procedures during oil change service. In October 2023, Hyundai published a Technical Service Bulletin (TSB) that provided detailed instructions for oil change service on its gasoline powered vehicles, specifically highlighting the need to remove and replace the existing drain plug gasket prior to reinstalling the drain plug. After a thorough review of the material submitted by the petitioner, the information already in NHTSA's possession, and the potential risks to motor vehicle safety implicated by the petitioners' allegations, NHTSA does not believe that a formal investigation is warranted. Therefore, the petition is denied. A Federal Register Notice (FRN) further detailing NHTSA’s reasons for denial of the petition will be published. The reference numbers for the complaints to NHTSA cited by the petitioner can be found in the petition submission documents in the public file for DP22-003. To review those complaints and the additional complaints ODI added to its evaluation which are cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

EA19001 · Electrical Overstress

Opened Apr 19, 2019 · Closed Sep 19, 2024

Status: closed (inferred from source dates) · Air Bags: Air Bag/restraint Control Module

The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect.  During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW.  The ECU receives signals from crash sensors mounted in the vehicle and deploys the vehicle air bags and seat belt pretensioners in accordance with manufacturer design specifications.  The ECU in the subject vehicles contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signal, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes). In September 2016, FCA announced recall 16V-668 for certain model year (MY) 2010 to 2014 Chrysler, Dodge and Jeep products manufactured with the subject ZF-TRW ACU.  In this recall, FCA discussed an EOS condition that resulted in a failure of the subject DS84 ASIC, which caused air bag non-deployment.  FCA noted that the defect condition had only been observed in vehicles equipped with sensor harnessing routed across the front of the vehicle.  Other FCA vehicles that also used the subject ACU, but were not equipped with cross-car harnessing, had not experienced EOS failures, despite similar time in service. During the course of this investigation, ODI sent two separate Information Request (IR) letters to six vehicle manufactures (including FCA, Hyundai, Honda, Kia, Mitsubishi, and Toyota) and one IR letter to ZF-TRW.  These IR letters resulted in ODI receiving comprehensive data from these manufacturers and suppliers. Studies of this data found that the DS84 ASIC does not have sufficient protection against negative electrical transients or electrical overstress (“EOS”) that can be generated in certain severe crashes.  An electrical transient occurs when the electrical power supplied to a circuit changes momentarily over a short duration of time.   In these severe crash cases, the crash sensors and other powered wiring can be damaged and short circuited so as to create a negative electrical transient of sufficient intensity and duration (that are outside the vehicle manufacturer's specification) to damage the ASIC before the restraint device deployment signal is received by the SRS ECU.  This damaged signal can lead to incomplete or nondeployment of the air bags and/or pretensioners.  Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.A total of 8 fatalities and 14 injuries were associated with known EOS events. The common element in all investigated manufacturers vehicles is the SRS ECU containing a DS84 ASIC manufactured by ZF-TRW.  The risk associated with the ASIC is equally shared among all OEMS involved in the investigation.  The actual real-world risk can be mitigated by other factors which were assessed by ODI during this investigation. The first mitigating factor involves protections built into the ACU design which protect the DS84 ASIC from damage.  There are multiple strategies and levels of protection employed by different OEMs that provide effective EOS mitigation.  The two most common strategies at the ACU level are circuit protection diodes on the remote senor signal lines, and current limiting resistors that protect critical components. The second mitigating factor is found at the vehicle level and involves the location and routing of the wires leading from the crash sensors to the SRS ECU.  If the wires are well protected in a crash and are not routed with other power wires carrying large currents, the risk for an EOS event is significantly reduced or eliminated. These design specific factors combine to produce a spectrum of risk for the vehicles equipped with ACUs using the DS84 ASIC.  Given the many of years of field exposure, it is possible to divide the subject population into two groups; vehicles which have experienced EOS events, and vehicles which have not experienced EOS field events. Four of the six OEMs involved in this investigation have experienced EOS field events on at least one of their models equipped with a DS84 ASIC.  All vehicle models (including the Toyota models identified in the Failure Report Summary of the opening resume for this investigation) with field events have been recalled.  In an abundance of caution, ODI kept this investigation open five years to monitor field performance and did not identify any field events on vehicles not included in existing safety recalls. Given the spectrum of risk identified in this investigation and that all vehicles with a demonstrated unreasonable risk have been recalled, ODI is closing this investigation. ODI is closing this investigation with the following manufacturer safety recalls: 16V-668, 18E-043, 18V-137, 18V-363, and 20V-024.  With the recall actions taken by the subject vehicle and equipment manufacturers, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exists on other model or model year vehicles outside of the recall scopes. The agency reserves the right to take further action if warranted by the circumstances.