503 of the 10,355 complaints filed about the KIA Optima are about the transmission — 5% of everything owners reported. The worst model year for it is 2016.
503
Complaints
5%
Share of all complaints
15
Crashes
7
Fires
POWER TRAIN
Loosing oil putting oil in every 3 to 4 days no leaks on ground or oil pan or drain plug.oil don't smell or looks burnt happened around did 2 oil changes in a week still the same. Car will sputer hesitation on acceleration every so often have all updateds and recalls.
NHTSA complaint #11757576 — an unverified report by a vehicle owner.
POWER TRAIN
The engine assembly completely seized and the vehicle is currently stored at an independent repair shop . While traveling at high speed on Interstate 4 on July 24, 2026, the vehicle suffered a sudden, catastrophic loss of power and stalled in live traffic, creating an immediate threat of a high speed rear end collision. An independent service center officially confirmed the engine seizure after a dealership failed to perform an inspection during an eight hour wait, and no law enforcement or insurance inspections have occurred. Prior symptoms included severe, recurring oil loss requiring constant manual additions of oil between regular service intervals (most recently serviced in June 2026 at a kia dealership), and eventually the car completely shutoff on July24.
NHTSA complaint #11754979 — an unverified report by a vehicle owner.
POWER TRAIN
the engine revs high and transmission wont shift and when you turn the steering wheel ya get a loud click and the steering wheels jumps
NHTSA complaint #11751411 — an unverified report by a vehicle owner.
POWER TRAIN
Engine replacement needed at 99,782 miles. P1326 code continuously popping up. Also has excessive oil consumption and electrical problems concerning the forward collision system. Kia refuses to replace engine although the P1326 code is covered by lifetime warranty. The cause of the incident was defect in engine resulting in a recall of all 2011-2019 models. The 2020 Kia optima LX contains a 2.4L GDI engine which has identical problems relating to previous lawsuits.
NHTSA complaint #11743902 — an unverified report by a vehicle owner.
POWER TRAIN
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 complaint #11742779 — an unverified report by a vehicle owner.
POWER TRAIN
I am reporting a recurring safety hazard involving my 2019 Kia Optima following a repair for diagnostic code P064A (Fuel Pump Control Module). Despite the dealership attempting to repair the fuel system, the vehicle remains in a 'limp mode' state. While driving, the vehicle began shaking violently and lost significant power, refusing to accelerate above 50 mph. This creates an immediate safety risk, as the vehicle cannot maintain highway speeds or safely merge, increasing the danger of a rear-end collision. The P064A code and subsequent 'limp mode' symptoms persist even after professional service. I am concerned that the existing Kia warranty extensions (such as WTY028 for the low-pressure fuel pump) or current repair procedures are insufficient to resolve this underlying mechanical/electronic failure, leaving the vehicle unpredictable and hazardous to operate in traffic.
NHTSA complaint #11742841 — an unverified report by a vehicle owner.
POWER TRAIN
Loosing oil putting oil in every 3 to 4 days no leaks on ground or oil pan or drain plug.oil don't smell or looks burnt happened around did 2 oil changes in a week still the same. Car will sputer hesitation on acceleration every so often
NHTSA complaint #11741793 — an unverified report by a vehicle owner.
POWER TRAIN
The Kia had a problem with the check engine light coming on and it gently went into limp mode. I had it repaired at Darlings Ford and it worked for about 600 miles. I had it repaired again and it worked for about 7,000 miles. The light recent came on and the car immediately hard banged andwent into limp mode. My wife was driving and shaking when she got home. The light went out and everything was fine. A couple of days later, on 5/27/26, we were on the interstate in traffic travelling 70 mph and it Violently hard bumped, the Cel came on and it went into limp mode. It was as if we hit deep pot holes with both front tires which we didn't as we were on a smooth highway. The light is still on and it's in limp mode.
NHTSA complaint #11740798 — an unverified report by a vehicle owner.
POWER TRAIN
Issue 1: High oil consumption in the engine due to poor engine design, according to the auto repair center. 5 quarts of oil are added to the engine once every 2-3 weeks. All oil leaks were previously repaired, but oil is still burning off. Issue 2: The engine has misfired more than once, with a puff of smoke coming out of the exhaust. Issue 3: Twice in the past 1.5-2 years, multiple spark plugs have failed, causing a breakdown. This is a Theta II engine, but it is not in the class action settlement.
NHTSA complaint #11738122 — an unverified report by a vehicle owner.
POWER TRAIN
Car is consuming oil every three weeks. Engine is going to burn if it does not stop. It’s not in a class action but probably should be. It’s been 4 months and over 1,000 spent.
NHTSA complaint #11737059 — an unverified report by a vehicle owner.
POWER TRAIN
Sudden engine failure while driving with no warning. Vehicle began jerking, shaking, and losing power. RPMs dropped unexpectedly and the engine stalled intermittently. Multiple misfire codes were present (cylinders 1, 3, and 4), and the engine was found to have low or no compression in cylinder 1. The condition rapidly worsened to near complete engine failure. The vehicle was operating normally prior to this incident. This failure is consistent with known Kia engine defects involving internal engine damage, including rod bearing failure. This is a safety concern due to sudden loss of power while driving.
NHTSA complaint #11734770 — an unverified report by a vehicle owner.
POWER TRAIN
The car starts and drives with other keys in ignition
NHTSA complaint #11731973 — an unverified report by a vehicle owner.
POWER TRAIN
My engine has failed. This is the second car I’ve had from Kia that the rod barring has failed.
NHTSA complaint #11728508 — an unverified report by a vehicle owner.
POWER TRAIN
The engine of vehicle repeatedly failed, causing the vehicle to stall while driving, which posed a serious risk to my safety and others on the road. The vehicle had approximately 65,000 miles and was maintained routinely and on schedule. The failure first occurred before November 18, 2025, when I reported stalling issues to Kia authorized service & parts. The vehicle was returned as “fixed” on December 12, 2025, but the engine stalled again during normal operation. The vehicle was returned to Kia authorized service & parts multiple times (December 12, December 18, December 23, January 9, January 12, 2026, and March 4, 2026), with repeated assurances that it had been repaired. Each time, the car continued to stall, including during a test drive at Subaru, demonstrating that the failure persisted despite repeated dealer intervention. The stalling created a significant hazard, as the car could lose power while on public roads, including highways, potentially leading to accidents. There were no consistent warning lights or messages prior to the engine stalling; the first symptom was intermittent loss of power while driving. The failure has been reproduced and observed by multiple service personnel at Kia authorized service & parts and by Subaru during the trade-in test drive. The component(s) causing the failure were inspected by Kia authorized service & parts staff, but no effective repair was made. Documentation of repair orders and dealer inspections is available for review.
NHTSA complaint #11727986 — an unverified report by a vehicle owner.
POWER TRAIN
The contact owns a 2013 Kia Optima. The contact stated that while a family member was driving the vehicle at 40 MPH, the vehicle stalled. There was no warning light illuminated. The driver pulled over to the side of the road where the vehicle failed to restart. The vehicle was towed to the residence, where an independent mechanic diagnosed the vehicle and determined that the engine and transmission needed to be replaced. The vehicle was not repaired due to the cost. The dealer and the manufacturer were not contacted or notified of the failure. The failure mileage was unknown.
NHTSA complaint #11727508 — an unverified report by a vehicle owner.
POWER TRAIN
Vehicle: 2013 Kia Optima SXL VIN: [XXX] While driving on a highway at approximately 55–58 mph, the rear driver-side electronic parking brake (EPB) motor housing failed with a loud bang. Immediately after, there was heavy smoke and a strong burning smell. The vehicle became very difficult to drive, and the wheel began screeching and dragging as if the brake had locked. The failure appears to have caused the rear brake caliper to seize while the vehicle was in motion. This created a dangerous driving situation at highway speed and could have caused a crash. The brake system component that failed appears to be the electronic parking brake actuator/motor assembly attached to the rear caliper. This was a sudden mechanical failure, not normal brake wear, and it occurred while driving at speed. Kia care case number: XXX INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11725980 — an unverified report by a vehicle owner.
POWER TRAIN
These cars have a known issue for burning oil the motor thats in my car was recalled for same issue but they are not trying fix my car under that recall of the bad motor that they did recall
NHTSA complaint #11723153 — an unverified report by a vehicle owner.
POWER TRAIN
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 complaint #11717931 — an unverified report by a vehicle owner.
POWER TRAIN
Odometer Fraud. The contact owns a 2008 Kia Optima. The contact stated that the check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed the vehicle's transmission failure. The contact discovered a mileage discrepancy after purchasing the vehicle. The vehicle was a dealer sale. At the time of purchase, the mileage was 198,000. It was later discovered that the mileage on the Title was 217,000.
NHTSA complaint #11716258 — an unverified report by a vehicle owner.
POWER TRAIN
My fiancée and I just recently bought this car with the 1.6T-GDi engine I immediately replaced the oil even though the dealership said that he just replaced it. I put 7 quarts of oil topping off from awk consumption after I initially changed the oil filter. Those 7 quarts were added over the period of three weeks and it’s just progressively gotten worse. I’m putting a quart to 1.5 quarts of oil in here every other day. Worried about it causing total failure & being at risk of being stranded with 2 kids due to the only engine I’ve been able to find that Kia doesn’t have any recall touched base on is the GAMMA 1.6 engine. The turbo GAMMA 1.6. The N/a 1.6 was covered but it has ungodly pop/clunking backfiring sound coming from either intake manifold or valve train please help. Times are hard enough as it is to be without a vehicle due to a fault other than none of my own the dealership extended powertrain warranty isn’t being honored by Kia even though they said it would just don’t want something to happen to me or the car that’s beyond my capabilities and knowledge and ultimately result in my spouse not having a reliable and/or safe means of transportation to/from work and commuting kids as well. Thanks in advance
NHTSA complaint #11715807 — an unverified report by a vehicle owner.