2015 Kia Optima Engine Problems

My energy in my car started messing up with only 150,000 miles it had a long knocking sound and it would not got over 20 miles while driving

NHTSA ID

11765682

Incident

Jun 10, 2026

My 2015 KIA optima experienced a catastrophic engine fire while I was driving. There was no warning, I just heard a boom in the engine bay the breaks stopped working and all electrical cut out. As I'm coasting, because I'm unable to stop, flames started to come in through under the dash. I couldn't turn the car off, nor put it in park so the doors stayed locked. The driver window was opened just enough for me to grab the top and break it, allowing me to crawl out. The car coasted itself to the shoulder then blew up (I had a full tank of gas.). All this happened in the manner of 30 to 35 seconds. It's important to note that KIA just replaced the engine 2 months prior to this incident.

NHTSA ID

11759158

Incident

Aug 14, 2026

The contact owns a 2015 Kia Optima. The contact stated that for over 8 years, the vehicle was experiencing excessive oil consumption. There was no warning light illuminated. The contact became aware that there was an oil leak on the ground underneath the vehicle. The vehicle was taken to the dealer on several occasions for the oil consumption failure; however, the dealer was unable to find a fault with the vehicle. The dealer had not yet provided a cause for the oil leak. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 123,000.

NHTSA ID

11758211

Incident

Aug 20, 2026

Mileage

123,000 mi

The engine in my vehicle failed while putting the car into reverse to back into my garage. I thank God I wasn't on the road when this happened. I took the car into a mechanic who confirmed that the engine was locked and that the car was very low on oil(even though I had my oil changed by him a few months prior). There was an undetected oil leak that led to the engine failure. The warning indicators didn't appear on my dash until after my engine failed.

NHTSA ID

11758113

Incident

Aug 14, 2026

This is a formal vehicle safety complaint regarding a manufacturer's active refusal to remedy a known safety defect under an active recall campaign guidelines.My 2015 Kia Optima Turbo experienced an active internal mechanical engine knock, violent sputtering, and a complete engine seizure. The vehicle is currently sitting un-driveable at an authorized Kia dealership.The required Knock Sensor Detection System (KSDS) software update was successfully completed on this vehicle prior to the incident, legally qualifying it for a 100% free long-block engine replacement under the manufacturer's active Lifetime Warranty extension. However, the dealership service department is actively withholding the safety warranty paperwork and refusing to submit the diagnostic photos and engine seizure data to corporate for warranty approval unless I agree to pay an additional $800 out of pocket for an external throttle body and O2 sensor.I have explicitly declined the retail accessory charges five separate times. I only authorize the replacement of my front sway bar links. Instead of separating the ticket and processing the free engine block safety remedy, the dealer is holding my safety warranty hostage to force a retail sale. Furthermore, a manufacturer consumer care representative recently refused to listen to my request on this matter and dropped the call.The manufacturer is using internal technical advice to block a court-ordered safety remedy and is allowing a dealership to use unauthorized retail accessory charges to deny me a safe, operating vehicle. I request immediate federal intervention to force the manufacturer to release the free engine block safety replacement order to the dealer and halt these predatory dealer practices.

NHTSA ID

11756632

Incident

Jul 27, 2026

The contact owns a 2015 Kia Optima. The contact stated that while driving at an undisclosed speed, the vehicle stalled. During the failure, several unknown warning lights flashed on the instrument panel and there was smoke coming from under the hood of the vehicle. The contact exited the vehicle, and there were flames coming from underneath the hood. The Fire Department was called to the scene and extinguished the flames. During the failure, the vehicle was destroyed. A Police report was filed, and the vehicle was towed to a tow lot. The cause of the failure was not yet determined. The manufacturer was notified of the failure. The contact stated that the original engine was previously replaced by the local dealer due to a previous recall. No further information was available. The failure mileage was 140,000.

NHTSA ID

11752336

Incident

Jul 17, 2026

Mileage

140,000 mi

My girlfriend was driving on interstate 95 to pick me up from the metro. The engine suddenly cut off in a manner that appears to have melted the wiring harness of the vehicle, risking fire. She was able to safely get to the side of the road and call a tow. After taking it to a local repair shop, they diagnosed the issue as related to the KSDS recall. We had it towed to the dealership that has also confirmed it is related to the recall. The engine is completely seized following this incident and it's worth noting that Kia is completely denying the engine repair claim as the KSDS update was not installed prior.

NHTSA ID

11751632

Incident

Jun 30, 2026

The contact owned a 2015 Kia Optima. The contact stated that while driving to the residence, the vehicle caught on fire. The contact stated that while at a traffic light, the vehicle suddenly shut off. After exiting the vehicle, the hood was opened, and there was smoke coming from the engine compartment. The contact called an independent mechanic and, within two minutes, became aware of the fire. The contact called 911 for the Emergency Services. The Fire Department arrived and extinguished the fire. There was no injury sustained. There were no warning lights illuminated. The vehicle was previously taken to an unknown local dealer, where it was diagnosed that the engine was leaking with a blown head gasket. The engine was replaced. The vehicle was towed from the scene and was deemed a total loss by the insurance company. The manufacturer was contacted and opened a case. The failure mileage was approximately 212,000.

NHTSA ID

11750336

Incident

Jul 8, 2026

Mileage

212,000 mi

While driving my 2015 Kia Optima, the engine failed completely without warning. The vehicle lost power while in motion approximately 300 miles away from my home. All warning lights illuminated and the car shut down during driving conditions, creating a serious safety hazard. The vehicle was towed to a Kia dealership where it was inspected. I was informed the engine has failed and may be related to the known 2.4L engine defect and prior recall campaign involving this engine type. This vehicle has a history of multiple recalls, including engine-related recalls issued in 2018 for the same engine family. The failure occurred suddenly and without prior adequate warning, and the vehicle is now inoperable. I purchased the vehicle in May 2023, and at the time of failure it had approximately 133,000 miles. The engine began knocking loudly prior to failure, then stalled and shut off completely while driving. This incident placed me and others at risk because the vehicle lost propulsion while in traffic. I believe this may be related to a known manufacturing defect in Kia 2.4L engines that has been the subject of recall and/or investigation. I am requesting that this complaint be documented as a safety-related engine failure potentially associated with the existing recall and that it be reviewed for further investigation and manufacturer accountability

NHTSA ID

11745917

Incident

Jun 15, 2026

1. What component or system failed or malfunctioned, and is it available for inspection upon request? The primary failure involved the engine. The vehicle experienced a major engine failure that resulted in an engine replacement under a manufacturer recall. After the replacement engine was installed, the vehicle later developed additional engine-related problems. An independent mechanic advised that the vehicle would require another engine replacement or extensive engine repairs. Additional defects included a malfunctioning moonroof that would no longer close properly and other mechanical issues affecting the vehicle's operation. The vehicle may be available for inspection depending on its current status and location. 2. How was your safety or the safety of others put at risk? The repeated engine problems created concerns about the reliability and safe operation of the vehicle. Sudden engine failure while driving resulted in loss of power, inability to maintain speed in traffic, and being stranded in unsafe conditions. The ongoing mechanical failures caused significant concern regarding the vehicle's dependability and safety. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The original engine issue was confirmed by authorized service personnel and resulted in an engine replacement under a manufacturer recall. The subsequent engine-related problem was evaluated by an independent mechanic, who advised that the vehicle required another engine replacement or significant repairs. 4. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle was inspected in connection with the original engine recall and replacement. It was also inspected by an independent mechanic regarding the subsequent engine issues. At this time, I am not aware of any inspection by police or insurance representatives related to these mechanical failures. 5. yes, right away

NHTSA ID

11745534

Incident

Jan 6, 2025

P1326 code flashing engine light knock sensor went out 3 times in 6 months and just replaced it again and this time engine light didn't go off I was reading that there was a recall on this but apparently mine doesn't state it. Car cannot pass emissions if engine light is on and the 15th of June is approaching. The car doesn't make any sounds or nothing.

NHTSA ID

11742779

Incident

Dec 13, 2025

The contact owns a 2015 Kia Optima. The contact received notification of NHTSA Campaign Number: 21V331000 (Service Brakes, Hydraulic); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that while starting the vehicle, the check engine warning light illuminated. The vehicle was take to O'Reilly's to be diagnosed. The DTC: P1326; was retrieved. The contact attempted to start the vehicle, but the vehicle failed to start. The contact researched online and found NHTSA Campaign Number: 20V543000 (Service Brakes, Hydraulic). The dealer was contacted, and it was confirmed that the vehicle was included in NHTSA Campaign Number: 20V543000 (Service Brakes, Hydraulic); however, the dealer refused to repair the vehicle because the vehicle was not currently registered and additional repairs were needed before a recall repair could be performed. The vehicle was being towed to the dealer. The vehicle was not yet repaired. The manufacturer was made aware of the issue. The failure mileage was approximately 137,000.

NHTSA ID

11742315

Incident

May 5, 2021

Mileage

137,000 mi

The contact owns a 2015 Kia Optima. The contact stated that while accelerating at 55 MPH, there was an abnormal burning smell detected. While driving, she was alerted by another driver who informed her that the vehicle was on fire. The passengers were able to exit the vehicle safely. The vehicle was engulfed in flames. There were no reported injuries. The vehicle was towed to a tow lot. The vehicle was previously taken to an independent mechanic, who said the engine was bad. The engine was previously replaced at 147,000 miles. The fire department was able to extinguish the fire. A police report was filed. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 60,000.

NHTSA ID

11740785

Incident

May 28, 2026

Mileage

60,000 mi

The contact owned a 2015 Kia Optima. The contact stated that while driving at 65 mph and slowing down to enter a parking garage, she observed black smoke emanating from under the hood, and the vehicle stalled. The contact then observed flames near the windshield wipers coming from under the hood of the vehicle. The contact exited the vehicle and called 911. She observed flames coming from under the hood and under the vehicle, and the vehicle became engulfed in flames. The contact stated that the garage manager attempted to extinguish the fire but was unsuccessful. The police and fire department arrived shortly after the attempt, and the fire department extinguished the fire. The contact did not sustain any injuries. A police report was not taken, and she was not aware of any fire department report being filed. The vehicle was bulldozed out of the parking garage and towed to a tow yard. The manufacturer was notified of the failure, and a complaint was filed. The failure mileage was 75,309.

NHTSA ID

11738851

Incident

Apr 28, 2026

Mileage

75,309 mi

Was driving down the interstate and the engine lost some power and the engine blew and parts of the connecting rod was on the outside of motor which blew a hole in the block and oil went into the intake manifold and pieces of the piston ring was in there and engine shut off, and seen that this has been a problem with these cars

NHTSA ID

11736696

Incident

May 8, 2026

Engine seized while driving.

NHTSA ID

11731047

Incident

Apr 10, 2026

Was driving then suddenly the engine shut off I was able to pull to the side Tried to restart it I saw smoke coming out from the hood I did tow it to my apartment looks like the engine is locked I contacted kia they said I have a branded title they can’t do anything about it Even if the car title was branded to a rear ending collision And the engine had oil in it

NHTSA ID

11725883

Incident

Mar 13, 2026

The contact owned a 2015 Kia Optima. The contact stated that while driving at 60 MPH, during a DoorDash delivery, the vehicle vibrated. The contact pulled to the side of the road and noticed smoke emitting underneath the vehicle from the right side. The contact exited the vehicle and noticed smoke emitting from underneath the hood. The state troopers were called. By the time the fire department arrived, the vehicle was engulfed in flames, and the engine had exploded. The fire department extinguished the fire. The contact was not injured. No police report was filed. The state troopers believed that the fire was caused by an electrical short. The contact stated that prior to the fire, the vehicle vibrated when idled. No warning lights were illuminated. The vehicle was towed to a towing yard. The insurance company was not notified about the fire. The contact was unaware that NHTSA Campaign Number: 21V331000 (SERVICE BRAKES, HYDRAULIC) was associated with the VIN. The manufacturer was not notified of the fire. The failure mileage was approximately 174,000.

NHTSA ID

11725022

Incident

Mar 17, 2026

Mileage

174,000 mi

The contact owns a 2015 Kia Optima. The contact stated that while driving at 40 MPH, there was smoke coming from underneath the hood, and the engine overheated. The check engine warning light was illuminated. The contact was able to pull over to the side of the road and add coolant to the coolant reservoir. The vehicle slowly started and was driven to the destination. The contact stated that the engine was overheating if driven for more than 10 minutes. The vehicle was taken to an independent mechanic, where it was determined that the vehicle was experiencing excessive coolant consumption, and coolant was added as needed. The mechanic determined that the failure might be related to the engine. The vehicle failed to start and was undrivable. The vehicle was not repaired. The dealer was contacted and referred the contact to the manufacturer for assistance. The manufacturer was contacted, and a case was filed. The failure mileage was approximately 124,000.

NHTSA ID

11721647

Incident

Feb 17, 2026

Mileage

124,000 mi

On Friday, February 27, 2026. This vehicle is being driven and vehicle seized and disabled on the road. In the middle of rush hour, traffic in a dangerous spot, local police had to be called out to assist, as no location was identified for a tow truck to be able to pick it up... The police had to dispatch their own tow service. After being towed from location where a car was disabled, mechanic looked at vehicle identifying there was no oil in the car. However on, September 9, 2025 an oil change was performed on the vehicle at 139,969 the car seized at 143,369.. That is approximately 3,399 miles driven from the time of the oil change up until the time it seized... There was no indicator lights that ever identified that an oil change was needed or low on oil on the vehicle prior to the car disabling..

NHTSA ID

11721582

Incident

Feb 27, 2026

The vehicle started making a loud knocking/tapping noise while driving. The vehicle has randomly acted as if it was going to stall while driving prior to the knocking. Instantly the car was brought home and parked. A mechanic has assessed the vehicle and states the noise we are hearing is the rods. We also contacted another mechanic and they advised us to look up the VIN due to a recall for 2015 Kia optima’s and the failure of this exact issue but we learned it was only for hybrid models even though this model has had the same exact issues as that model. I then see there have already been complaints made for my same issue and model yet no recall campaign has been initiated. I am fearful to drive or try to sell this vehicle because what if someone else drives it and it does stall again during driving and injury or death occurs.

NHTSA ID

11720091

Incident

Oct 6, 2025

Engine seized and won’t turn at all

NHTSA ID

11719754

Incident

Jan 7, 2026

Engine failure while driving on freeway. Almost hit by semi truck. Towed to Dealership. Engine check light flashing complete loss of power. Kia refusing engine replacement under settlement.

NHTSA ID

11719695

Incident

Feb 20, 2026

On December 27, 2025, at approximately 150,556 miles, my 2015 Kia Optima Hybrid experienced sudden engine knocking, power loss, and failure while driving at 65 mph on a highway. The vehicle dropped into limp mode and I had to pull off the highway. The car required towing to the dealership as it would not drive safely. Diagnostics revealed a knock sensor error (P1326 code) and failing connecting rod bearings via Bearing Clearance Test, consistent with the known Theta II engine defect (manufacturing debris causing oil starvation and premature bearing wear). This follows earlier symptoms: Intermittent 'Check Hybrid System' warnings in early December 2025 at 148,665 miles (dealership unable to reproduce, but historical codes noted). The Knock Sensor Detection System (KSDS) software update was performed in February 2022 during prior CHS warnings. Despite onset of issues under the 150,000-mile extended warranty limit per the Kia E2 Settlement, Kia denied coverage due to the minor mileage overage and directed me in a loop between Consumer Assistance and the Settlement Administrator. The defect poses a serious safety risk: potential for sudden engine seizure, stalling while driving, or engine compartment fire (as seen in related Theta II recalls and thousands of NHTSA complaints). No crash, injury, or fire occurred in my case, but the failure left the vehicle undrivable and unsafe on the road. I have service records and diagnostic reports to support this.

NHTSA ID

11717931

Incident

Dec 27, 2025

Valve cover leaking and oil dripping oil on exhaust at 114k miles. Risk of engine fire.

NHTSA ID

11716870

Incident

Feb 1, 2026