2018 Kia Optima
Problems, recalls and owner-reported issues
Engine is the leading concern among 232 owner complaints filed for this model year. This is the 8th highest complaint count among 20 Optima model years with reports.
Of the 2018 reports, 10 involved a crash and 10 involved a fire. 9 people were injured.
What owners report most often
Recalls and investigations
Latches/locks/linkages, trunk lid, latchAug 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."
A person inside the trunk compartment may become trapped, increasing their risk of injury.
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.
Campaign 23V594000 on NHTSA.gov
Hybrid propulsion systemMar 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.
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.
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.
Campaign 18V161000 on NHTSA.gov
Representative owner complaints
232 reports, newest first.
Electrical system, Engine, Fuel/propulsion system, Nov 5, 2025
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)
Other or unspecified, Oct 13, 2025
Trunk latch broke leaving it impossible for someone in the trunk to get out and very difficult for someone on the outside to open the trunk
Engine, Oct 7, 2025
I’ve had my car for 6 months and it constantly burns oil I’ve had 4 oil changes because it Is completely disappearing but my mechanics can not find any leaks. Then I changed all my spark plugs and two were completely burnt and they were changed a month ago and now one of them went again and this time is completely covered in oil
Engine, Sep 28, 2025
The engine of my 2018 Kia Optima is burning oil. When it started, I had 72,000 miles, and it's burning one quart of oil every thousand miles. There is no oil leak. I will take it back to Kia on October 2, 2025. The mechanic reported that it has an internal engine issue.
Engine, Sep 24, 2025
The oil consumption is burning at a faster rate than normal. My oil changes are always on time but for months I have been having to take it for an oil change about 2,000 miles below mileage time. I have had it inspected but found no oil leaks. This is a major problem for the engine and safety.
Engine, Sep 22, 2025
Engine seized and stopped working. While I could not find any recall information based on the VIN, it is a 2018 Kia which was subject to the Kia Engine Settlement (In re: Hyundai and Kia Engine Litigation , No. 8:17‑cv‑00838‑JLS‑JDE and Flaherty v. Hyundai Motor Company, et al. , No. 18‑cv‑02223 (C.D. Cal.)). Was never notified of such settlement as the VIN would have triggered this notification by Kia but they obviously did not list this in the recall.
Engine, Sep 18, 2025
I was driving on the highway with my children and the engine started to knock and lock up. I had to swerve onto an exit and roll into a gas station. My check engine light was on. I had it serviced in 2023 at a kia dealership. I had electrical issues to my battery that I opted to get fixed elsewhere. The dealership was aware of the recall on my engine, when I had it towed to them in 2025. Dealership said I opted out of a recall on my engine.
Engine, Sep 17, 2025
Car would convulse and shake very wildly metal parts spread around engine. It has very rough idle. 4th cylinder went out and car only has about 99060 miles. The valve went out. My safety was very bad as car was not driving safely and shaking like a person having a seizeure each time it would stop. Vehicle has been inspected by a Kia dealer. This problem I had seems to get an issue many other people with Kia Optima have.
Engine, Sep 8, 2025
My 2018 Kia Optima has a cracked oil pan, which caused an excessive oil leak —up to 5 quarts in a matter of hours. This eventually led to my engine going out.
Engine, Sep 4, 2025
Car suddenly stopped working; it was struggling to stay on. Mechanic stated cylinder is not functioning at full force.
Electrical system, Exterior lighting, Aug 19, 2025, fire
My cars bulbs have been blowing on a regular basis for two years..some of the bulb connections are catching fire and exploding .Ive changed on numerous occasions but doesn’t matter even with new fittings…obviously an electric problem
Engine and engine cooling, Aug 18, 2025
The contact owns a 2018 Kia Optima. The contact stated that while driving at various speeds, the vehicle hesitated while depressing the accelerator pedal with the oil warning light flashing on the instrument panel. The contact's friend initially inspected the vehicle and discovered that the engine oil was empty. The vehicle was taken to a dealer where a diagnostic test was performed, and the mechanic discovered oil around the engine; however, the source of the leak was not discovered. The contact was informed that an engine valve was sealed and that the failure was repaired. Despite the repair, the failure persisted, and the oil light was frequently illuminated on the instrument panel. The engine oil level was checked and was extremely low. The dealer had not offered any additional assistance for the repair. The vehicle was not repaired. The contact made several attempts to reach the manufacturer but was unsuccessful. The failure mileage was approximately 10,000.
Engine, Aug 3, 2025
My 2018 Kia Optima went into limp mode while exiting the freeway. I had it scanned and received a P1326 code, which is directly tied to the known engine knock sensor / bearing wear issue in Kia models. The engine light came on and the car lost power suddenly. This created a very unsafe situation. I contacted Kia, and they confirmed that my VIN is not included in the engine recall (KSDS campaign), even though my symptoms exactly match the covered vehicles. I am now stuck with an undriveable car and no recall coverage, even though I’m facing the same failure risk. I believe this VIN should be included, and that this is a clear safety issue. I am requesting the NHTSA to investigate and push Kia to expand coverage to include more affected vehicles.
Engine, Fuel/propulsion system, Jul 18, 2025
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.
Engine, Jul 15, 2025
Kia is aware of the engine oil consumption causing misfires, failed emissions test, blowing a rod and engine lock up. THEIR SOLUTION WAS A CLASS ACTION LAWSUIT THAT STATE ONCE THE CAR IS LOCKED UP OR ROD HAS BLOWN THROUGH THE ENGINE THEN THEY WILL FIX IT. I HAVE HAD TO ADD OIL AT LEAST 3 TIMES EVERY 3000 MILES AND CONTINUE TO REPLACE THE OIL FILTER AS WELL. THE SPARK PLUGS HAVE BEEN REPLACED MUTLIPLE TIMES ALSO TO HELP WITH THIS ISSUE. KIA ADVISED THAT MY VEHICLE DID NOT FALL UNDER THIS RECALL EVEN THOUGH MY VEHICHLE IS HAVING THE SAME ISSUES AS THE RECALL STATES. THIS IS A KNOWN ISSUE WITH THIS MAKE AND MODEL AND THEY SHOULD NOT BE ABLE TO GET AWAY WITH SELLING DEFECTIVE VEHICLES AND NOT REPAIRING THE ISSUES THEY KNEW THEY HAD PRIOR TO SELLING THE VEHICLES. SOMETHING NEEDS TO BE DONE.
Engine, Jul 11, 2025
Engine failed despite maintenance and repairs. The car is part of the active class action for Kia Engine Defects. The KSDS software was never installed as we were never notified about the recall by kia. As a result, Kia denied coverage under the engine defect class action settlement. We need this vehicle repaired or compensation for replacement
Vehicle speed control, Service brakes, Fuel/propulsion system, Jul 10, 2025
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
Electrical system, Engine, Jul 9, 2025
The car is literally burning through oil so bad every other week I am putting more in, the electrical system continues to fail and shorts, the motor sounds like it is ticking now due to the oil consumption.
Engine, Jul 3, 2025
The 2.4L Theta II engine in my 2018 Kia Optima is failing, exhibiting excessive oil consumption, with oil loss documented at over 1 quart per 1,000 miles, leading to secondary failures in the catalytic converter, clogged with oil carbon and breaking into pieces that may damage the cylinder walls, and the spark plugs, which are fouled with carbon, causing misfires. The engine and related components remain intact and un-repaired, pending Kia’s required 3,000-mile consumption test. Safety of drivers have been put at significant risk. The excessive oil consumption and potential engine seizure threaten sudden loss of power, especially on freeways where car fails to accelerate to city and highway speeds, increasing the chance of a collision. The clogged catalytic converter poses a fire hazard, (reported by NHTSA investigations into Theta II) where oil leaks or debris can ignite on hot surfaces. Risk is heightened during the mandated 3,000-mile test as well. Problem has been confirmed by both a dealer and an independent service center as recent at 1 July, '25, documenting oil loss and new engine recommendation. Symptoms began with noticeable oil loss during oil changes, starting at least 1 quart per interval on May 10, 2023 (mileage 43,374), with the loss increasing over time. Misfires and RPM loss during acceleration first appeared after the oil valve gasket replacement in late May 2025, and freeway pickup issues became apparent around mid-June 2025. The full engine failure was confirmed by Spitzer on July 01, 2025.
Engine, Jun 15, 2025
Got an oil change, and they advised that it was low on oil. (I had just replaced it recently) I took it to the dealer and they advised a part was bad, that they replaced. I was driving and the check engine light and oil light came on . I had to tow car. Dealer said the engine was burning oil, and that the engine is covered, but I would have to drive it until it got worse.
Engine, Jun 12, 2025
Subject: Urgent Request for Engine Replacement – 2018 Kia Optima Dear Kia Consumer Affairs, I am writing to formally report a recurring and increasingly dangerous engine issue with my 2018 Kia Optima, and to request immediate assistance, including consideration for an engine replacement due to ongoing safety and reliability concerns. Since June 2024, I have routinely visited the Kia dealership on a near-monthly basis for service due to persistent problems with excessive oil consumption and spark plug failures. Each visit has resulted in service-related expenses, despite my efforts to maintain the vehicle in accordance with manufacturer recommendations. Unfortunately, the issue has not been resolved and continues to worsen. Most recently, on [XXX], I experienced a critical incident. While driving, the engine began shaking aggressively, the check engine light illuminated, and smoke was detected coming from the engine compartment. Out of concern for my safety, I immediately pulled over and had the vehicle dropped off at a nearby garage for emergency inspection. This incident, combined with the repeated monthly service visits and associated costs, clearly indicates a systemic issue that may be linked to known engine defects in similar Kia models. I urge Kia to review my case for warranty coverage, recall eligibility, or goodwill engine replacement assistance. I have attached supporting documentation including service records, receipts, and oil consumption logs. Please advise on the next steps for resolving this matter. Thank you for your attention. I look forward to your prompt response. Sincerely, [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Power train, Electrical system, Engine, Jun 4, 2025
There is already the theta 2 campaign on my Kia optima but Kia is not upholding their warranty for a new engine. Kia customer care told me that untill my car actually throws a rod then they will not fix it. So I could be doing 80 down the freeway and jeopardize not only my safety but everyone else's for them to uphold their lifetime warranty? Also upon doing further investigation and I don't know how many cars this pertains to but the fuse box in my 2018 actually belongs to a 2016 which if you look it up yes they are comparable but don't offer all the same functions or power that my 2018 needs to run I fully believe Kia knew this when they were being built on the factory line because it just so happens that there is about 6 different versions to the pcb relay that can fit from a 2016 to a 2020 k5 but for some odd reason every car got something different why?
Engine, May 23, 2025
The contact owns a 2018 Kia Optima. The contact stated while driving 70 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal. The contact turned off the cruise control; however, the failure persisted, and the vehicle stalled. The contact stated that the check oil warning light was illuminated. The contact was able to coast to the side of the road. The vehicle failed to restart, and the vehicle was towed to a service station. The vehicle was then towed to a dealer where it was diagnosed and determined that the high-pressure fuel pump had failed, causing fuel intrusion into the engine and engine failure. The vehicle was not repaired due to the cost. The manufacturer was not made aware of the failure. The failure mileage was approximately 146,000.
Air bags, May 22, 2025, crash
The contact called on behalf of his son who owned a 2018 Kia Optima. The contact stated that while driving at approximately 25 MPH, the front of the vehicle crashed into the rear end of the vehicle that was in front of him whom made a sudden stop. The contact was concerned that the air bags were not deployed. No warning lights was illuminated. A police report was filed. No medical attention was sought, and no injuries were sustained. The vehicle was pronounced totaled at the scene. The contact attempted to contact the manufacturer however, received no response. The failure mileage was 96,145.
Engine, May 14, 2025
This vehicle has an active recall: SC218 / DTC P1326 – ECU UPDATE / ENGINE REPAIR. I brought it to Martin Kia in Newark, Delaware, but they refused to perform the recall stating that since the vehicle is owned by a used car dealer, the recall is not applicable. They also provided a written statement saying that the extended warranty does not apply because I am a dealer, and that they will not perform any recall work until the vehicle is owned by a “customer.” However, federal law requires all safety recalls to be completed free of charge, regardless of the vehicle’s current ownership status or whether it is owned by a dealership. This is a safety issue and refusal to perform recall work puts future drivers at risk. I have attached the letter they gave me for your reference. I kindly request your urgent review of this case and enforcement action to ensure the dealership complies with federal recall obligations.