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2018 Kia Optima problems

The most common problem on the 2018 Kia Optima is engine and cooling, typically around 72,800 miles. Its complaint count is close to a typical Optima model year.

Typical yearClose to a typical year
Year score
72/100
Owner complaints
233
Recalls
2
Service bulletins
155
Worst area
Engine
Fuel economy
25-40mpg
Typical repair
$650

The worst 2018 Kia Optima problems

Ranked by number of owner complaints. Mileage and cost come from what owners wrote.

Problems by type

Tap a problem to see which part fails, at what mileage and in which other years.

Specific symptoms reported on the 2018 Kia Optima

Oil consumption 54Check engine light 39Engine failure 30Stalling 29Knocking 23Jerking 15Fire or smoke 13Headlights 13Misfire 11Loss of power 10Won't shift 8Hesitation 7Fuel pump 6Won't start 6

Trouble codes owners of the 2018 Kia Optima mention

P1326 7

Recalls 2

Latches/locks/linkages: trunk lid: latchReported August 24, 2023 · 319,436 vehicles affected
What is wrong
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."
Risk
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.

Recall number 23V594000 · Recall details

Hybrid propulsion systemReported March 8, 2018 · 1,710 vehicles affected
What is wrong
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.
Risk
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 number 18V161000 · Recall details

See all 2 recalls for the 2018 Kia Optima

Defect investigations

Loss of Motive PowerOpened September 12, 2022, closed December 12, 2023

the federal safety agency 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 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 the federal safety agency 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 the federal safety agency's possession, and the potential risks to motor vehicle safety implicated by the petitioners' allegations, the federal safety agency does not believe that a formal investigation is warranted. Therefore, the petition is denied. A Federal Register Notice (FRN) further detailing the federal safety agency’s reasons for denial of the petition will be published. The reference numbers for the complaints to the federal safety agency 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

DP22003

Electrical overstressOpened April 19, 2019, closed September 19, 2024

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 the federal safety agency 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.

EA19001

Technical service bulletins for the 2018 Kia Optima 155

Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.

See all 155 bulletins for the 2018 Kia Optima

2018 Kia Optima fuel economy

Official EPA estimates in miles per gallon (MPGe for electric). Ranges cover trims that share the same engine.

EngineDriveCityHighwayCombined
2.0L 4‑cyl Plug-in hybridFWD384340
1.6L 4‑cylFWD283731
2.4L 4‑cylFWD23-2532-3626-29
2.0L 4‑cylFWD223125

What 2018 Kia Optima owners say

Most recent owner complaints, unedited.

Filed Oct 21, 2026 · Engine, Transmission · CA

My 2018 Kia Optima has the Theta II 2.4L engine. In February 2026, the dealer performed an engine/powertrain computer reprogramming. In August 2026, the engine failed and the vehicle was taken to an authorized Kia dealer, where the engine was replaced under the Theta II engine warranty. The vehicle was at the dealer from August 8 until the repair was completed on September 29, 2026. When I picked up the vehicle on October 9, it felt shaky and vibrated on the drive home. On October 11, the vehicle began giving off a distinct, unfamiliar smell that is not like burning fuel or oil. On October 21, I found the vehicle leaking an opaque, milky tan fluid onto my garage floor. The type and source of the fluid are UNKNOWN. I have photos of the leak. My family and I have stopped driving the vehicle because we believe it is unsafe. We were driving it with our children before these symptoms appeared. Given the history of Theta II engine failures, we are concerned about the risk of engine failure, stalling, or fire while driving. The new symptoms have not yet been diagnosed or confirmed by a dealer. I am arranging for the vehicle to be towed to a Kia dealer for warranty diagnosis. The vehicle and leak are available for inspection. I have reported these issues to the manufacturer under an open customer case.

Filed Sep 8, 2026 · Engine · 126,000 miles · FL

The contact owns a 2018 Kia Optima. The contact stated that upon starting the vehicle, the vehicle jerked abnormally. The failure persisted while driving, and the vehicle lost motive power. The contact was able to restart the vehicle; however, the failure persisted while driving. The vehicle was towed to a dealer to be repaired under an unknown recall for an engine software update and key fob replacement; however, the dealer failed to honor the recall repair and recommended purchasing a new vehicle. The manufacturer was contacted by phone, and a case was filed. The failure mileage was approximately 126,000. The VIN and License plate number were unavailable.

Filed Aug 20, 2026 · Engine · 136,000 miles · GA

The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, the vehicle failed to accelerate and failed to exceed 52 MPH. The vehicle shut off. The contact stated that the engine was running rough while stationary and the vehicle shut off without warning. The vehicle was taken to an Auto Parts Store, where it was diagnosed, and it was determined that the vehicle was in LIMP Mode with knock sensor codes displayed. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 136,000.

Filed Jul 22, 2026 · Engine · FL

See attached document for complaint.

Filed Jul 19, 2026 · Airbags, Seat belts · PA · crash · 1 injury

I was run off the road by a drunk driver I hit a tree at 35MPH MY AIR BAGS DID NOT DEPLOY NOR DID MY SEAT BELT LOCK!!!! I NOW HAVE MULTIPLE INJURIES I HAVE BROKEN BONES ALL THROUGHOUT MY FACE!!!!! A SEVERE CONCUSSION!!!!! Any time I call the the customer care center and try and get information or call someone I either get hung up or gave the run around and then hung up on my mother in law has also tried calling and have received the same response this is so unacceptable and unprofessional.

Filed Jul 9, 2026 · Engine · PA

I’ve had my 2018 kia optima for round about two years.I only got this car because they refused to replace my previous engine on my 2015 Kia optima,even though I had a warranty but that’s another story(Kia on the Blvd).This car have given me problems from the start.Going through oil in less than a month,which they can never find a leak,not being able to go over a certain speed before I start to hear noises.Ive complained about noises,they act like they can’t hear,and said nothing is wrong with the engine when previously checked.My check engine light has came on twice and both times the car was malfunctioning on the highway resulting in me have to get a tow.First it was plugs replacement now I need a whole new engine.I really don’t know what to do at this point.I believe they sold me a faulty car

Filed Jul 2, 2026 · Brakes · WI

Purchased vehicle from a used car dealership. Had it a few months before brake pedal started losing pressure and going to floor. Had master cylinder replaced. A few months later, brake light started coming on when accelerating. New master cylinder had leaked into brake booster. Had master cylinder replaced along with brake booster. A few weeks later and brake pedal is losing pressure again

Filed Jun 25, 2026 · Engine · MO

The car burns oil within a week of getting an oil change. It was only driven a 200 miles before all of the oil was burned out. This has been a consistent issue with this car that the oil burns at an extreme rate. This is a safety risk as it could lead to engine overheating, the engine could stall out due to the fast burning of the oil, or a potential fire hazard while driving. The oil light will come on for a second and at that point, the oil is already EXTREMELY too low. I brought the car to the mechanic and they have told me multiple times that there is no leak or anything. The mechanic says that the car simply is burning oil too fast.

Filed Jun 23, 2026 · Engine · 1,500 miles · ID

The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, there was an abnormal odor and a knocking sound coming from the engine. The vehicle was taken to the dealer; however, the dealer was unable to duplicate the issue. The vehicle was not repaired. The issue persisted. The contact stated that the vehicle was later returned to the dealer to be repaired under a service campaign involving the engine control unit (ECU). Shortly after the vehicle was repaired, the ECU failure message was displayed. The vehicle subsequently became inoperable. The vehicle was not repaired. The manufacturer was notified of the issue. The approximate failure mileage was 1,500.

Filed Jun 10, 2026 · GA

2018 Kia Optima Dealer Ed Voyles Kia Smyrna began Recall SC340. Vehicle drove in running. Dealer flashed ECM software, discovered non-original engine/ECU. Vehicle now won’t start. Dealer document states 'will not start after recall.' Dealer refuses to restore to running condition citing prior repairs. This violates 49 USC 30120

Used buying checklistWhat to check on a 2018 Kia Optima before you buy

Compare the 2018 Kia Optima

Optima vs Honda AccordOptima vs Ford FusionOptima vs Chevrolet MalibuOptima vs Toyota CamryOptima vs Hyundai SonataOptima vs Nissan AltimaOptima vs Volkswagen PassatOptima vs Subaru Legacy

Other model years

20012002200320042005200620072008200920102011201220132014201520162017201820192020

Questions about the 2018 Kia Optima

Is the 2018 Kia Optima reliable?

Owners have filed 233 complaints about the 2018 Kia Optima, close to a typical Optima model year.

What is the 2018 Kia Optima year score?

The 2018 Kia Optima scores 72 out of 100 (average). The score compares it with the other model years of the Kia Optima: 75 is a typical year, 50 means twice the usual complaints, and serious complaints and recalls lower it.

What is the most common problem with the 2018 Kia Optima?

Engine and cooling, with 144 complaints, typically around 72,800 miles. Next is electrical (33).

How many recalls does the 2018 Kia Optima have?

2 recalls, covering latches/locks/linkages and hybrid propulsion system.

What gas mileage does the 2018 Kia Optima get?

Official estimates for the 2018 Kia Optima range from 25 to 40 mpg combined. The most efficient version (2.0L 4-cyl plug-in hybrid, FWD) gets 38 city and 43 highway.

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