general problems of the 2015 Kia Motor Optima - part 1

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.

Engine seized while driving.

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.

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.

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. .

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.

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.

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

The contact owns a 2015 kia Optima. The contact stated that while driving at an undisclosed speed, the engine seized, and the vehicle stalled. The vehicle was able to coast to the side of the road. The check engine warning light and several other warning lights were illuminated. The contact raised the hood, and there was a burning odor coming from the engine. The vehicle was towed to the place of employment. A mobile mechanic arrived at the place of employment and used a handheld code reader to diagnose the vehicle, but no dtc was retrieved, and no cause for the failure was determined. The starter was replaced; however, the vehicle failed to restart. The vehicle was towed to an independent mechanic, who diagnosed that the engine had failed and needed to be replaced. The vehicle was not repaired due to the cost. The contact stated that the vehicle was purchased six months prior to the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 96,000.

I've had car for not very long and rid bearings now all of a sudden went out and engine is bad at this point and don't understand why my vehicle wouldn't be included in all the different recalls for 2015 Optima because it's one of the years of theta 2 engine being recalled and mine says 0 recalls why is that?.

Engine seized and won’t turn at all.

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.

My 2015 kia Optima (VIN [xxx] ) experienced sudden engine failure and stalled while driving at approximately 90,000 miles. There was no oil pressure warning light and no knocking prior to failure. The check engine light illuminated shortly before the stall. Kia is denying engine coverage solely because an ecu/ksds update was not performed. I was never notified of this update because kia had an incorrect address on file for me. This failure is consistent with known theta ii connecting rod bearing defects that have resulted in recalls and warranty extensions. I believe this is a safety-related defect and am requesting review. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Engine seized.

The engine in my 2015 kia Optima suddenly seized due to connecting rod bearing failure at approximately 55,000 miles. This vehicle is known to be affected by the theta ii engine defect. I was never aware of the seriousness of the recall software update and did not receive meaningful notice that failure to install it could result in catastrophic engine failure. Kia has denied engine warranty coverage solely because the software update was not installed prior to failure, despite the defect existing regardless of software.

The contact owns a 2015 kia Optima. The contact stated that while driving at an undisclosed speed, the engine seized. The contact stated that the check engine warning light was illuminated several minutes before the engine seized. The vehicle was towed to an independent mechanic, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The vehicle was then towed to the dealer where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact was informed that the repair was not covered under warranty. The manufacturer was made aware of the failure but provided no assistance. The contact was informed that because the previous owner did not have an unknown software update performed, the repair was not covered under warranty. The failure mileage was approximately 138,000.

12-01-2025 driving to work in the morning approx 7:00a. M. And turned on the heater and had a very strong smell like fuel so immediately turned it off. Cracked my windows to air it out and then was super cold again and had turned on the heater to try again. Immediately had to turn it off and rolled windows down to air it out because the smell was intense and had started to feel nauseas. Later in the day, about to head to lunch and had started the vehicle and smelt a lot like gas and turned it off and had someone come out to double check the smell. Co worker had strong smell from the hood area and looked underneath the car and can see a little drop puddle. Opened the hood and lifted the cover to engine where you can see the leakage coming from the center hose and spill puddle. Service tech came to take a look and advised its the fuel feed to the high pressure pump. This is a safety concern because fuel is extremely flammable and can put myself in dangerous situation of firing igniting in the car or hurt others around. No check engine light and prior the vehicle incident car has been consuming oil putting in about 1- quart a week or so with commute miles about 270 weekly.

The incident took place on Sunday, December 30th. I was driving to pick up my children from their father and on our way home my car stopped accelerating entirely. This had only happen one other time a few days prior. I was in a gas station parking lot and initially when I turned my car on and went to put it into drive it wouldn’t accelerate. I thought that was odd so I did the only thing I knew how to, I checked my oil levels. Levels were full and no other issues were there. The check engine light had popped up when I turned my car back on but my car did accelerate so I thought nothing of it. I took my car to auto zone for a diagnostic and they told me my “b cam shaft” sensor needed to be moved and that could be causing the engine light to come on and ticking in my motor. I called a few shops getting quotes and eventually was forced to tow to the closest shop to me after my car refused to start overall. They replaced the battery and the b cam shaft censors and still were unable to get the car started. They told me 3 recalls were open on my car, including the motor and to have it towed to kia for a full replacement. After calling kia to have the repairs done, they refused me service based on a previous owner not handling prior recalls.

The contact owns a 2015 kia Optima. The contact stated that while driving at an undisclosed speed, the engine seized. The contact stated that the failure had occurred while driving on the highway. No warning lights were illuminated. The contact used a portable diagnostic machine but failed to retrieve a fault code. The vehicle was towed to an independent mechanic, where it was diagnosed with engine failure. The vehicle was not repaired. The contact was advised to tow the vehicle to the dealer. In addition, the contact was informed of an unknown recall for the year, make, and model vehicle. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. In addition, the contact was informed of an unknown recall; however, the VIN was not under recall. The contact was advised to contact the NHTSA hotline to report the failure. The manufacturer was made aware of the failure but provided no assistance. The contact was informed that the vehicle was purchased used. In addition, the contact was informed that the recall mileage limit was 100,000. The failure mileage was approximately 99,325.

The contact owned a 2015 kia Optima. The contact stated that while driving at 55 mph, while depressing the accelerator pedal, the contact could smell a burning smell within the vehicle, and then he noticed smoke coming from the front of the vehicle. No warning lights illuminated. The contact pulled over to the right side of the road and exited the vehicle, opened the hood, and noticed smoke and flames coming from the engine. The contact exited the vehicle and stood on the side of the road, and called 911. No injuries were sustained. No medical attention was required. The contact mentioned the police showed up on the scene; however, he could not remember if he received a police report. A fire department report was filed. The fire department extinguished the fire. The vehicle was destroyed. The vehicle was towed to pro-cars. The vehicle was not repaired. The contact mentioned he contacted his insurance company, and they informed him that the vehicle was a total loss. The manufacturer was notified of the failure, and they transferred him to the escalation department and informed him that an inspector would inspect the vehicle, and he had to wait seven to ten business days for a resolution. The failure mileage was 53,000.

The contact owns a 2015 kia Optima. The contact stated that while driving at 40 mph, there was an abnormal knocking sound coming from the engine. No warning light was illuminated. The vehicle was taken to the dealer, where it was diagnosed with engine failure, and the contact was informed that the engine needed to be replaced. The contact stated that the dealer refused to repair the vehicle. The contact was informed that the hecu recall repair needed to be completed first. The contact was unaware that the vehicle was included in NHTSA campaign number: 21v331000 (service brakes, hydraulic). The vehicle remained at the dealer unrepaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 77,000.

While driving my 2015 kia Optima (VIN: [xxx] ) at highway speed, the engine suddenly shut off without any warning lights, alerts, noises, or check-engine indicators. This created a dangerous situation for me and surrounding drivers. The vehicle had passed state inspection only 3 months earlier with no issues. The sudden shutdown is consistent with the known theta ii engine defect investigated by NHTSA. The car is now completely undrivable. Two kia dealerships refused to assist, claiming that they cannot perform ksds because the engine is already dead. These reasons directly contradict the kia theta ii engine settlement terms. This sudden stall is a safety hazard and could have caused a severe crash. I am requesting that NHTSA review this incident as a potential recurrence of the engine-stall defect already documented in Hyundai/kia vehicles. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My engine failed in my 2015 kia Optima. I took it to the kia dealership in my city, and was advised to provide documentation of oil changes. In which I did, and was told that coverage for the engine recall was denied due to one gap where I went roughly 15,000 miles without an oil change. When asked when this gap was, they stated in 2021, and I asked how can I get documentation of that if I don’t have the receipt from that long ago. They stated that they need documentation to be able to approve the engine to be covered under the recall. It has been advised that kia would have to prove exceptional neglect, in which one gap from 2021 is not exceptional neglect. I called the kia. Customer service complaint line and filed a complaint with a case number, and was told that there’s nothing they can do without that documentation from that one gap. In which I asked to escalate this to a manager or supervisor and was told I could not do that. When I called the kia dealership to see options, all they kept doing was trying to persuade me to just buy a new car asking don’t you just want a new car. I am without a vehicle and I have two kids that I need to help get to and from school doctors appointments as well as after school activities. I do not believe that a one gap should disqualify you from coverage of an engine under the recall.

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.

While driving my 2015 kia Optima I was getting ready to turn in to my residence. My car completely shut off but my lights had got dimmed. So I had it towed to the kia dealership then proceeded to tell me it has three recalls on it. Then a customer service representative said that I would have to pay $200,and something dollars to have my car diagnostic done. Whoever I replied even with these recalls I have to pay for diagnostic test to be done she replies yes,but I’m thinking they are just trying to make money off customers.

9/25/2025 - our vehicle suddenly stopped in the middle of a busy roadway creating a hazard. We had it towed to [xxx] kia of greenville. 9/26/2025 we were advised that the engine had seized with no symptoms and no warning lights. The technician said that it would be covered under the vehicles extended warranty due to the known defect/class action on the theta ii gdi engine documented here: [xxx] 10/2/2025 we were advised the car would not be covered under the warranty due to some conflict on a carfax report. According to carfax, the vehicle has 82k with 15 maintenance records. This was not a case of neglect by the owner, it is a known defect that kia is not willing to fix. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2015 kia Optima. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power. There was no warning light illuminated. The vehicle was not able to restart. The vehicle was towed to the residence. The dealer was not contacted. The vehicle was diagnosed or repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 127,000.

The contact owns a 2015 kia Optima. The contact stated that while his son was driving at 60 mph, the instrument panel was entirely illuminated, and he pulled over. There was smoke inside the cabin. The occupants were able to exit the vehicle. An independent mechanic opened the hood and noticed a fire. They were able to extinguish the fire. The vehicle was towed to the local dealer, where it was diagnosed that the drive belt had failed and had broken. There was friction from the drive belt, which caused the fire. The vehicle was not repaired. The manufacturer was contacted, who opened a claim. The manufacturer had called the contact, but no further assistance was provided. The approximate failure mileage was 114,000.

My engine recently sustained damage. Although my vehicle’s VIN is listed in the affected recall range, I never received any safety recall notification. I purchased the car in January 2024 while the ksds recall was still active, yet no one informed me of the recall at the time of sale and I have received no updates since.

The car just shut off.

The contact owns a 2015 kia Optima. The contact stated while driving approximately 65 mph, there was an abnormal knocking sound coming from the engine compartment before the vehicle stalled. The vehicle was towed to the local mechanic who diagnosed and determined that the engine had failed and needed to be replaced. The manufacturer was notified of the failure and advised the contact to tow the vehicle to a local dealer for assistance. The vehicle was towed to the local dealer but was not repaired. The failure mileage was 60,000.

All recalls were not done false input information they never fixed engine bearing recall I’m getting a consultant to handle all the false information being provided by kia federico in woodriver.

My motor bearing is knocking very loud I was refused service upon arrival dealer was making my service very complicated asking me to go dig up old receipts and various other things that was not actually caused for and I was at risk by driving the car there until it shut off due to engine failures when the car has fire risk and could possibly explode and they have confirmed it’s the engine but have not done any maintenance to my engine the check engine light flashes heavy non stop as well was even denied a loaner car still until today.

While driving, the engine suddenly shut off without warning. The car coasted to a stop and would not restart. When attempting to start it again, the starter smoked, and the engine would not crank or turn over. This is a serious safety hazard as the engine failure occurred with no warning and matches the symptoms of the known kia theta ii engine recall for bearing and seizure issues. My VIN is not currently listed as part of the recall, but it experienced the exact same failure. I am requesting that NHTSA investigate and pressure kia to include my VIN in the recall campaign, as this is a sudden engine seizure defect that could cause a crash if it happens at speed.

The engine seized and is out of commission on 7/16/25.