2018 Kia Optima: engine failure

Filed Oct 21, 2026 · Engine, Transmission · CA

My 2018 Kia Optima has the Theta II 2.4L engine. In February 2026, the dealer performed an engine/powertrain computer reprogramming. In August 2026, the engine failed and the vehicle was taken to an authorized Kia dealer, where the engine was replaced under the Theta II engine warranty. The vehicle was at the dealer from August 8 until the repair was completed on September 29, 2026. When I picked up the vehicle on October 9, it felt shaky and vibrated on the drive home. On October 11, the vehicle began giving off a distinct, unfamiliar smell that is not like burning fuel or oil. On October 21, I found the vehicle leaking an opaque, milky tan fluid onto my garage floor. The type and source of the fluid are UNKNOWN. I have photos of the leak. My family and I have stopped driving the vehicle because we believe it is unsafe. We were driving it with our children before these symptoms appeared. Given the history of Theta II engine failures, we are concerned about the risk of engine failure, stalling, or fire while driving. The new symptoms have not yet been diagnosed or confirmed by a dealer. I am arranging for the vehicle to be towed to a Kia dealer for warranty diagnosis. The vehicle and leak are available for inspection. I have reported these issues to the manufacturer under an open customer case.

Filed Jul 9, 2026 · Engine · PA

I’ve had my 2018 kia optima for round about two years.I only got this car because they refused to replace my previous engine on my 2015 Kia optima,even though I had a warranty but that’s another story(Kia on the Blvd).This car have given me problems from the start.Going through oil in less than a month,which they can never find a leak,not being able to go over a certain speed before I start to hear noises.Ive complained about noises,they act like they can’t hear,and said nothing is wrong with the engine when previously checked.My check engine light has came on twice and both times the car was malfunctioning on the highway resulting in me have to get a tow.First it was plugs replacement now I need a whole new engine.I really don’t know what to do at this point.I believe they sold me a faulty car

Filed Apr 28, 2026 · Engine · VA

2018 Kia Optima LX, 2.4L GDI Theta II engine. Approximately 128,000 miles. Reporting severe internal oil consumption that has progressed to engine misfire and shaking, consistent with late-stage Theta II connecting rod bearing failure. The vehicle is now unsafe to drive and has been parked. Timeline: Purchased as a Certified Pre-Owned vehicle in December 2021. Excessive oil consumption began shortly after purchase. For approximately 4.5 years I have added about 1 quart of oil every 2 weeks to keep the engine from running dry. No external leaks have ever been found by any mechanic. Multiple independent mechanics attempted diagnosis and repair over this period. None resolved the issue. The vehicle has now developed a pronounced shake and apparent engine misfire, the textbook progression to rod bearing failure documented in the federal safety agency investigation PE19-004 and prior recalls/campaigns 17V‑224, SC147, and SC172. Safety concerns: Sudden engine seizure or stall at highway speed creates a serious crash risk for me and surrounding traffic. Theta II 2.4L GDI rod bearing failure has been associated with under-hood fires. The defect develops gradually with no warning to the driver beyond elevated oil consumption, which is frequently dismissed as normal until catastrophic failure occurs. I am filing this complaint to document the failure and to add to the federal safety agency's data on the Theta II GDI 2.4L engine in 2018–2019 Optimas. This model year was excluded from the original 2017 recall but is included in the Hyundai and Kia Engine Litigation class settlement and the lifetime engine warranty extension. My vehicle's symptoms match the defect pattern exactly. I will pursue warranty engine replacement, but I want this safety failure on the federal record regardless of how Kia responds.

Filed Apr 15, 2026 · Engine · GA

Consuming fuel to the amount of roughly 1/2 quart per 150 miles. Vehicle has been inspected by mechanic and the oil pan, oil filter, and PCV valve has been replaced and engine oil UV dye added and cycled with no leaks found. The risk is that if not rigorously checked often, the engine will malfunction because the car runs out of oil. I have had my mechanic checking this car since I purchased it in January 2026. We have had to replace the oil pan and do two full oil changes with three separate quarts of oil being added in between all of that to keep it topped up. My mechanic agrees that the engine is consuming oil at an extremely high rate. My mechanic and a mechanic at the dealership where I purchased it are the only one who has inspected the car for this issue so far. The mechanic at the dealership is who recommended we replace the oil pan to see if that fixed the leak, which my personal mechanic did. Yes the critical engine failure lamp illuminates on the dashboard when the oil ran out the first time while I was driving it. This was how I discovered that there was an oil leak. This specific incident occurred three weeks after I purchased the car which I bought in mid-January of 2026.

Filed Mar 11, 2026 · Body, Engine · GA

My teenage daughter regularly drives this vehicle. The vehicle began experiencing significant oil consumption, oil leaks, and intermittent loss of power. During an early inspection at an independent repair facility, a check engine code P1326 was identified. Due to the symptoms and diagnostic code, the repair facility advised that the vehicle could be heading toward engine failure and recommended that the vehicle be taken to an authorized dealership because potential engine issues may fall under manufacturer warranty coverage. The vehicle was then towed to an authorized dealership. During the first visit, the dealership retained the vehicle for an extended period of time, approximately two months. During that visit, several recommended services were completed, including replacement of spark plugs, ignition wires, and replacement of the valve cover gasket along with other recommended maintenance. During that visit, it was also stated that the vehicle has a known issue with excessive oil consumption. Because of this, the oil level is checked weekly and oil is added as needed. I also informed the dealership that the independent repair facility had identified code P1326, but I was told that the dealership diagnostic codes were different. After these repairs, the vehicle experienced another incident where it lost power and began idling roughly while being driven on a busy highway. The vehicle was taken back to the dealership. During that visit, it was stated that the fuel injector harness and oil pressure sensor needed to be replaced. The dealership also indicated that the spark plugs needed to be replaced again, even though they had been replaced at the same dealership less than a year earlier. At that time, I asked if the vehicle would be safe to drive for approximately one week because I needed to travel out of town and my daughter would need the vehicle. The dealership advised that it was safe to drive during that time. The vehicle was then brought back to the deal

Filed Jan 7, 2026 · Electrical, Engine · CA

I was sold an unsafe vehicle at J and J Auto house 6446 Wilshire Bl LA,CA 90022. Dealer withheld condition of car . Had car three months and was stranded on highway. Car was towed to Kia dealer and diagnosed with complete engine failure. Dealer will not honor limited warranty, shady sales practices withheld recall info during sale, won’t allow his mechanic to look at car, dodged calls, denied request to return car for refund

Filed Dec 10, 2025 · Engine · NM

While driving my 2018 Kia Optima S, the car suddenly jerked, lost power, and stalled in traffic. Multiple warning lights came on at the same time including the oil light, battery light, and check engine light. I had no acceleration and the brakes became very hard to press. The vehicle had to be towed for safety reasons. The Kia dealership inspected the vehicle and confirmed internal engine failure due to “cylinder failure” and stated the engine needs complete replacement. This failure occurred without any external leaks and without warning other than the sudden loss of power. The dealer stated the issue is not covered, even though it is clearly an internal engine malfunction. This is a major safety hazard because the stall happened while I was in active traffic. A sudden loss of power and braking ability puts me and others at risk of an accident. The problem has been confirmed by the Kia dealership through diagnostic testing. The vehicle is still available for inspection. Warning lamps appeared only at the moment of failure, giving no advance warning. This appears to be related to the ongoing engine defects in Kia vehicles involving oil starvation, loss of compression, cylinder scoring, and internal engine failure. Cylinder failure and sudden stalling should be investigated as part of the known safety-related engine defects affecting this model.

Filed Sep 22, 2025 · Engine · CA

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.

Filed Jul 18, 2025 · Engine, Fuel system · GA

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.

Filed Jul 11, 2025 · Engine · GA

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

Filed Jul 3, 2025 · Engine · OH

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 the federal safety agency 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.

Filed Jun 12, 2025 · Engine · MD

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)