2018 Kia Optima Engine
Owner-reported problems and safety issues filed with NHTSA. Review common failures, severity levels, and complaint trends over time.
Complaint Timeline
Chronological view of owner reports
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.
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.
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 replace the spark plugs multiple times in last 12 months due to misfires while driving. I HAVE BEEN TOLD BY THE DEALER THAT THEY CANT DOING ANYTHING TO HELP EVEN THOUGH THEY ARE AWARE THEY SUGGEST THAT I DRIVE WITH NO OIL AND LOCK THE ENGINE UP EVEN THOUGH IT COULD CAUSE A CRASH. MY LIFE SHOULD NOT BE PUT IN DANAGER FIRST IN ORDER FOR THEM.TO FIX THE ENGINE.
Complaint-Car misfired, oil leaking on spark plugs causing an Engin Replacement that was first complained to Gossett Kia Covington Pike,1900 Covington Pike, Memphis, Tn 38128 on [XXX].On [XXX] complaint car shakes, misfire. Complaint to Gossett Kia South 2680 Mt.Moriah Rd, Memphis, Tn 35115. This date car stayed at dealership 3 days invoice a diagnostic was performed total amt $913.38. On 12/26/24 Mr.Macias on Mt.Moriah asked me to bring my vehicle in for another diagnostic test, amt to be charged $251.00 this time a tune up, replaced #4 spark plug that had misfired, fuel injectors cleaned I asked Mr.Macias "why would I have that done when it had been done the month before, the Tech recommended Engine Replacement. I also asked the above, what about the Tech's findings, Mr.Macias stated he would get back with me. On 1/16/25 Mr.Macias called to discuss Engine replacement (Projected Amt:$6,300). I have contacted Kia Consumer Assistance on 1/10/25 to discuss all of the above to no avail. I have been without a vehicle since 12/3/26 I am continually getting the run around, I have all invoices to verify my dilemma with a vehicle that is sitting unused. I am a [XXX] who is still making a $484.00 car payment per month. I've done my research on the 2018 Kia Optima's, only to find that the same problem that I'm having with the oil leaking on the spark plugs, misfiring , shaking, causing stalling in the middle of traffic, if this is not a hazard, what is ? This a problem that should have been corrected long ago. I would appreciate it if you would please help me. I'm tired of having to pay to get to and from Dr's. Office visits, drug stores and grocery stores. Thanking you in advance, [XXX] [XXX] or email address : [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Increased oil consumption with needing oil added and or changed half way before date or milage stated, oil changes performed by Kia dealer. Car staling and engine knocking while driving. Burnt smell while driving.
The contact owns a 2018 Kia Optima. The contact stated that while his daughter was driving at an undisclosed speed, the check engine warning light illuminated, and the vehicle went into LIMP Mode. The vehicle was towed to an independent mechanic, who related the failure to NHTSA Campaign Number: 17V224000 (Engine and Engine Cooling); however, the VIN was not included in the recall. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 106,000.
1- My 2018 Kia Optima engine seized while driving on interstate 64 West -Had the car towed to a mechanic (J TEAM AUTO REPAIR) and was told me to contact kia because after replacing the spark plugs and coils and knock sensor there was still no compressing in cylinder 4. My life and safety was at risk when my engine blew out on the interstate. When I went to Kia Dealership they confirmed that my VIN number was included in the recall and in the class action lawsuit. customer support told me since I wasn't the first owner of the car they weren't required to honor the recall -I asked why I was never informed they told me I bought the car as second owner my 60,000 warranty has expired and the extended warranty for engine doesn’t cover compression issues - its stated on the NHTSA website that they are required to send notices to all owners.When I contacted (Escalation Case specialist) with this information they said the extended warranty only covers the rod bearing connectors, and not compression. Completely contradicting the first call I had with another employee at Kia. Kia is deliberately keeping people in cars with engines that were manufactured improperly. I had the KSDS update-It takes more than reading engine codes to get to the bottom of things. Compression is part of the engine block. Prior to the Engine failure, my Kia Optima, was constantly burning oil.
The contact owns a 2018 Kia Optima. The contact stated that the vehicle was consuming an excessive amount of engine oil. The engine and oil warning lights were flashing on the instrument panel. The vehicle was taken to the local dealer, who performed an oil consumption test. The vehicle failed the oil consumption test and determined that the vehicle was consuming an excessive amount of engine oil. The vehicle was not repaired. The vehicle was taken to another local dealer, Monroeville Kia (3721 William Penn Hwy, Monroeville, PA 15146); who informed the contact there was no recall coverage on the VIN for the failure. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was unknown.
Car cut out and stutters and the engine light flashes. Code P1326 is displayed on the OBD reader.
My engine started leaking oil from the inside and all of a sudden my car started shaking out of nowhere
The contact owns a 2018 Kia Optima. The contact stated while driving approximately 40 MPH, the vehicle was losing motive power. The contact stated that there were no warning lights illuminated. The contact stated that the vehicle stalled. The contact was able to stop; however, after numerous attempts to restart the vehicle, the contact had the vehicle towed to the residence. The vehicle was later towed to a local dealer who inspected the vehicle and determined that the engine had seized and needed to be replaced. The contact stated that prior to the stall, the vehicle had been consuming an abnormal amount of engine oil. The contact stated that he was adding a quart of oil every week. The vehicle was not repaired. The manufacturer was informed of the failure. The contact researched online and related the failure to NHTSA Campaign Number: 17V224000 (Engine and Engine Cooling). The failure mileage was approximately 82,000.
The contact owns a 2018 Kia Optima. The contact stated while driving 20 MPH, the vehicle hesitated upon depression of the accelerator pedal with the check engine warning light illuminated. The contact continued to drive the vehicle however, the vehicle failed to accelerate above 40 MPH and was shaking abnormally. The vehicle was not diagnosed or repaired. Neither the dealer nor the manufacturer was notified of the failure. The failure mileage was 132,378.
Have completed 4 oil consumption tests and replaced knock sensor and now have knocking in the engine
Code P-030300 was detected when doing a diagnostic on my car when the check engine light came on. It is a cylinder 3 misfire. When the car comes to a idle the car starts to shake roughly. I took it to the KIA dealership I bought the car from and they told me I would need a new engine and not to drive it.Thankfully nothing bad happened while my baby was in the car. I drove it home and stopped driving it completely once the issue occurred.
Engine continuously stalls,while driving in both city and hight way. I have taken it in while under warranty and am told that's just how the car runs. Sudden jerks / seizure will happen while driving. since I haven't gotten the vehicle it happens at min 15mph or on the freeway at 65 mph. It is stalls at all mph .
Took my vehicle for an oil change next day my vehicle was not working well stopped on me could start didn’t want to do damage so I stopped driving and had it told to a shop found out there is METAL IN THE ENGINE
Car burning excessive oil in engine. 2 quarts every 1,200 miles
Oil consumption issue. My mechanic referred me to Kia because oil consumption. I would bring car in because oil light and no oil in car and had oil change only 1000 miles. Kia did 2 checks one at 1000 miles and one at 500 miles and oil consumption failed both times. Now I have to pay $686 for oil combustion cleaning even though I am being told this is more than likely going to have engine replaced by Kia because of known issues,
The contact owns a 2018 Kia Optima. The contact stated that after starting the vehicle, there was an abnormal amount of smoke coming from the exhaust pipe. The contact inspected the dipstick and discovered that the engine oil level was low. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 60,000.
The contact’s sister owns a 2018 Kia Optima. The contact stated that the vehicle was consuming an excessive amount of engine oil. The contact stated that engine oil needed to be added every 2-3 weeks. The contact stated that an unknown warning light was illuminated. The vehicle received an unknown repair; however, the failure persisted. The vehicle was taken to the dealer and was diagnosed with valve cover gasket failure. The valve cover gasket was replaced however, the failure persisted. The failure persisted and the vehicle was taken to an independent mechanic where it was discovered that there was an oil leak as well as there was excessive oil consumption. The independent mechanic stated that the engine might need to be replaced; however, a diagnostic result was not confirmed. The vehicle had not been repaired. The manufacturer was not made aware of the failure. The failure mileage was 98,000.
It started with the car using oil but the mechanic could not determine where the oil was going. It quickly lead to the Cadillac converter going out with a host of other things that cost me over $2900 to fix. Which only lasted a few weeks and the last incident occurred when I was on my way home and it would not pick up speed at all and would stall. The first time it happened I was on the free way and it lost speed almost causing a semi to run into the back of me. The second time I was at a red light and when I tried to accelerate in speed and it stalled and then began to jerk before it would pick up speed. Each time the occurrence happened it placed my life as well as my families life in danger as it was sudden with no engine light or any other lights coming on. The last time it happened it left me stranded with a child, over 2 hours from home and in the middle of the night on isolated highway. Every time I would call KIA they would give me the run around on the issue and say it was due to my negligence but I beg to differ as I feel as if it is an engine error on the manufacturing. Please help. Currently the car is sitting in my yard and I can not afford to keep paying for repairs due to a faulty engine that they refuse to fix.
My 2018 Kia Optima experienced an oil consumption issue. After awhile out of nowhere my vehicles oil light kept coming on. There was zero oil in my garage. Unbeknownst to me It was burning oil due to this oil consumption issue.I took it to multiple mechanics all which told me that this issue is a known issue and would eventually blow the engine, which is exactly what happened. I reached out to Kia in person via dealerships over the phone via their consumer line and they went out of their way to tell me all the reasons why they could not replace the engine. I have spent enormous amounts of money on rental cars and Ubers and Lyfts to get to work or appointments just to Because of this issue . I was referred to this organization by the Ga consumer bar help line.
Indiana - car in reverse in driveway and started shaking. I turned car off and back on and it drove normally. The next day, I put the car in reverse and the shaking started again and check engine light illuminated. This car has a history of burning oil and we constantly have to add oil between oil changes. Car is at Andy Mohr Kia dealership at this time where we were told that engine would not be covered by Warranty because we are second owners. Mileage of car is 62,000 miles.
My vehicle is constantly running out of oil within a 30 day period and I constantly getting an oil change. I was advised to get an oil consumption test at the dealer and was out of oil in 3 weeks. I was told that I have a warranty, however, it's only if the rod bearings are an issue. I think my engine should be replaced without paying a $300 diagnostic fee that might get refunded without an exact time frame.
I drove the car to the park about 6 miles round trip with family. I came back home and started having lunch for about 25 minutes. I then attempt to start the engine to go to my appointment but then car didn't turn on. On third attempt I had a weird noise coming out of the hood and I went back inside the house to get my gloves. When i came outside of the house, the hood of the car was in flames. I called 911 to turn off the fire. The car is now at a total loss.
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The 2018 Kia Optima has 90 Engine complaints on file. 1 crashes have been reported. Review the timeline above for detailed owner experiences.