Engine And Engine Cooling Problems of Hyundai Sonata - part 1

Unknown- while driving on highway, from 70 mph speed the car suddenly lost acceleration and speed dropped. No response to accelerator. Even with pushing the accelerator high, car will go in high rpm and speed will barely reach 40 mph. I was lucky that there was no other vehicle behind me, especially heavy automobile like semi truck as it would have crashed in me from behind due to sudden propulsion loss. The car started working fine next day. I took it to dealer and they couldn't find any error code but said it could be 12v battery bms software update and they updated it. They mentioned that this is not a safety issue which is mind-blowing and concerning as this is a major safety hazard. I would request you to investigate this further and if this is a software issue then please direct Hyundai to update this with all vehicles and cover the cost for those who have had to pay for it.

See all problems of the 2023 Hyundai Sonata 🔎.

My 2014 Hyundai Sonata experienced a p1326 engine fault code, which activates the knock sensor system due to engine bearing wear. This condition is directly related to Hyundai’s safety recall 17v226 (theta ii engine). The Hyundai dealership submitted my case to Hyundai corporate, and Hyundai denied the repair solely because my vehicle has over 150,000 miles. A manufacturer cannot refuse a federal recall repair due to mileage, and Hyundai’s engine recall has no mileage or time limit. The denial places me in an unsafe situation, as the recall defect can cause engine seizure or stalling while driving. I am requesting NHTSA intervention.

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The contact owns a 2018 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the low oil warning light illuminated. The vehicle was taken to the dealer, but was not diagnosed or repaired. The dealer advised the contact to have an oil change performed and then return the vehicle after 1,000 miles of driving. The contact stated that after returning the vehicle to the dealer, the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 99,000.

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My Hyundai is experiencing severe and continuous engine oil consumption that creates a safety risk. The vehicle loses a significant amount of oil within 1,000–1,500 miles, sometimes showing almost no oil on the dipstick despite recent oil changes. There are no external leaks, no burning smell, and no visible oil under the car. The cause remains unknown, but it appears to be internal engine burning or a manufacturing defect. I have taken the vehicle to the Hyundai dealer multiple times. They performed oil consumption tests but either reported “normal results” or did not provide clear explanations. The issue continues exactly the same. I also contacted Hyundai corporate, but no meaningful assistance or goodwill support was provided. The dealer acknowledges no leaks but still refuses to repair or replace the engine. This problem is dangerous because the oil level drops without warning lights or error codes. If I do not manually check the dipstick, the engine could run dry and seize while driving. Sudden engine failure on highways or in traffic can cause accidents. I now have to frequently top up oil just to keep the engine alive. I have maintained the vehicle properly and completed all requested tests. The cause is still unknown, but based on similar Hyundai cases, it may involve piston rings, valve seals, or internal engine wear. Many Hyundai owners report the same issue, suggesting a broader defect. The dealer’s only advice is to “keep monitoring oil,” which is not a safe long-term solution. This defect poses a serious safety concern and financial burden. I am filing this complaint so NHTSA can investigate, as the engine may fail unexpectedly, putting me and others at risk.

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The contact owns a 2013 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the vehicle stalled, with an abnormal knocking sound coming from the engine compartment. The check engine warning light was illuminated. The contact was able to restart the vehicle; however, the failure persisted. The contact previously received notification of NHTSA campaign number: 17v226000 (engine and engine cooling). The vehicle was taken to the dealer, where it was diagnosed, and determined that the engine short block had failed and needed to be replaced. The contact was informed by the dealer that the vehicle would not be serviced under the recall. The contact was offered a buyback option for the vehicle and was also offered a loaner vehicle. The vehicle was not yet repaired. The manufacturer was made aware of the failure. The failure mileage was not available.

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Vehicle: 2013 Hyundai Sonata VIN: [xxx] mileage: [163,000] summary: theta ii 2. 4l gdi engine bearing failure (recall 953 / 20v-393) – severe knocking, risk of sudden engine seizure/fire. Dealer refuses lifetime-warranty repair and forced consumer to pay towing to avoid lien/fees. Description: this vehicle is covered by NHTSA recall 20v-393 (campaign 953) and the court-approved theta ii engine class-action settlement providing a lifetime warranty for rod-bearing failure. The engine now has loud knocking from failed rod bearings – the exact defect addressed by the recall and settlement. On 11/28/2025 I dropped the vehicle at group 1 Hyundai southwest houston (10301 southwest fwy, houston, TX 77074) for diagnosis and repair under the lifetime warranty. The dealership confirmed bearing failure but refused to repair, stating the vehicle is “not eligible” because the free campaign 953 knock-sensor software update was never performed. No owner (current or prior) ever received any recall notice or settlement notice despite Hyundai’s legal duty to notify all registered owners. On 12/04/2025, service advisor tevin told me to remove the car by Friday or face storage fees and possible lien sale. To avoid unlawful charges for a known safety defect, I paid $192. 70 out of pocket for aaa to tow the vehicle off the lot on 12/05/2025 (receipt available). Hyundai is using its own failure to provide notice as justification to deny legitimate lifetime-warranty claims and shift costs to consumers. The unrepaired vehicle remains a serious safety hazard (engine stall/fire risk) on the road. Requested action: investigate Hyundai motor America and its dealers for (1) systemic failure to notify owners of recall 953 and the theta ii settlement, (2) wrongful denial of lifetime-warranty engine repairs, and (3) imposing towing/storage fees on consumers for admitted safety defects. I have filed a claim with the settlement administrator and can provide receipts, recorded calls, and docs. Information redacted pursuant to the freedom of information a.

My car was having an issue where it was losing all the coolant, causing my engine to overheat twice while driving down the highway. Unfortunately I couldn't find a leak anywhere and there was no fluid leaking in my garage. I lost an entire reservoir of coolant overnight. After taking my car to the dealership to get repaired, I was told that it was leaking my coolant into the exhaust system and burning it up. I was also told "it was a know issue, they had a bulletin from Hyundai on how to fix the problem, and Hyundai completely redesigned the part to stop the leak and it had to be special ordered. " I was without my car for a week and left with a $1300 bill as apparently it was not covered by my warranty. I have no idea how a known issue is happening so frequently that requires a nationwide bulletin and a part redesign, yet somehow is recalled. Especially considering it left me stranded on the side on the side of the highway in indiana during a snow storm but someone seriously needs to investigate it.

I bought this vehicle as a certified pre-owned from a Hyundai dealership on 09/10/2022 with 32,677 miles. Around 85,000 miles, it began burning an excessive amount of oil—about two quarts per month. Now, with approximately 101,000 miles, it still burns two quarts weekly, oil is being expelled from the muffler, and the exhaust has started to glow red. I have tried contacting Hyundai but have not received any response.

My car is blowing a large amount of white smoke due to the head gasket being cracked, I was quoted 2 grand to fix it. The car is not old enough to need a new head gasket, this is completely due to how the car manufactured and I have seen many other reports of this, there should be a recall and this should be fixed free of charge.

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My 2015 Hyundai Sonata has a defective engine. The motor failed unexpectedly even though the car has low usage and has always been maintained properly. I was informed that many Hyundai engines from these years came with manufacturing issues, and mine appears to be one of them. I am requesting that Hyundai replace the engine or provide a proper solution since this defect is not due to misuse but a faulty motor that came from the manufacturer. I need this resolved as soon as possible because the car is not running at all.

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On 11/28/25 at approximately 6:30 pm, I was driving on a highway 17 going about 60 mph when my car's engine completely shut down. A "hybrid system failure" warning flashed and my car was no longer drivable. The car was towed to the dealership. In mid October 2025, my car stopped running with the same "hybrid system failure" warning, but it happened in my driveway. The car was towed to the dealership and supposedly repaired.

While I was driving at approximately 55mph, a loud clank happened and the car stalled, and smoke started pouring out of the hood and through the vents into the cabin, and I was leaving burning pieces behind on the road. I pulled over, ran to the back to get my dogs out of their crash tested kennels in the backseat, and both rear doors & passenger front door were locked. I ran up front to unlock them, and the unlock button did not work. I tried the unlock on the keys and it did not work. Due to having a recommended crash safe kennel set up it was not possible to crawl into the back to open it from the inside. My dogs were trapped in a car that was filled with smoke and on fire for over 2 minutes while I debated breaking the windows. I managed to fish a wire into the back to unlock and pull the door open from the inside of the back doors. The car stopped burning but was still smoking for several minutes after & I was able to clear the smoke to make it safe for my dogs to wait for a tow. When the mechanic looked at it he said the engine blew up due to the rod shattering into the block, destroying the entire engine and spilling oil which lit on fire. Mechanic recommended I contact Hyundai for engine replacement as this was a known issue with other 2015 Hyundai Sonatas which were recalled due to risk of a defect rod knock causing the rod to shatter causing high speed stalling. Hyundai says my engine was not included in that specific recall. I included photo of the shattered rod which fell out when the mechanic lifted the vehicle.

I am filing a complaint regarding Hyundai motor America’s handling of my engine-related safety issue, buyback process, and rental reimbursement. My vehicle was towed to elder Hyundai for a suspected engine failure. Elder Hyundai informed me that my car was covered under an engine recall campaign and that they would submit a request for free repair. Shortly afterward, Hyundai motor America notified me that they would not perform the repair and that I was being forced into the buyback process under a settlement agreement release (sar). Elder Hyundai refused to provide me a loaner vehicle because I was not proceeding with repairs, despite the issue being part of an engine recall. They also refused to give me the repair order report for my records and refused to let me retrieve my personal items from my vehicle unless I paid a diagnostic fee. Hyundai motor America told me I was covered under them for this fee, yet elder Hyundai still refused. Regarding transportation, I was initially told Hyundai does not reimburse turo rentals due to concerns about “fake receipts. ” because of my budget and age, turo was the only rental option I could afford. After escalating, a supervisor approved reimbursement for my turo rentals, but as of today I have not received any reimbursement. I am a school teacher with a two-hour commute each day and I have [xxx] twin toddlers. I had to use rent and bill money to pay for the rentals based on assurances that reimbursement would be processed within a week. I submitted all receipts, but my new case manager claims he has no record of them, further delaying reimbursement. I completed and returned all sar buyback documents on November 15th, yet I have received no update on payment or processing. This entire ordeal has put me at financial risk, including potential job loss and housing instability. Hyundai’s delays and mishandling of this safety-related case have severely impacted my livelihood. I ask that you please review hma’s action information redacted pursuant to the freedom of informa.

My 2013 Hyundai Sonata qualifies for a lifetime warranty engine replacement under the theta ii class action settlement. The dealership is refusing coverage unless I provide maintenance records, even though the settlement prohibits denial based solely on missing records or the presence of sludge. Hyundai must prove neglect caused the failure, which has not been demonstrated. I am requesting review by the engine settlement team and approval of my engine replacement.

Car stalls and shuts down while shifting to park or reverse and when slowing to turn or stopping. Also the media screen will black out and not work at times.

My 2018 Hyundai Sonata’s oil light flashed briefly while driving, so I checked the oil level and found the dipstick completely dry. The car has been maintained regularly and was still about 1,000 miles away from its next scheduled oil change. There are no visible leaks, and the engine is not smoking. I had to immediately add oil to prevent engine damage. This appears to be a case of excessive oil consumption, which I have since learned is common in Hyundai Sonatas with this engine. I am very concerned that low oil pressure could cause engine failure or sudden loss of power while driving, creating a serious safety hazard. I request that NHTSA investigate this issue for 2018 Sonatas, as many owners are reporting similar experiences, and Hyundai has issued a technical service bulletin (TSB 23-em-008h) about excessive oil consumption but no recall.

Car started misfiring while driving and engine light came on. It kept losing power but I was able to pull off highway. This put myself and others in danger because speed was significantly reduced suddenly. Dealer said problem was due to oil leaking on spark plugs. The car had been using excessive oil. Dealer said this is known issue but I had to pay for any repairs since I was the second owner. Hyundai still pays for the original owner to get an oil consumption cleaning, but recently stopped paying for secondary owners. If the oil consumption cleaning does not work, then the next step is to replace engine, paid by customer if Hyundai refuses. Mileage on car is 75,769.

New battery keeps dying, car not starting and when it does start it shuts off when I brake. Oil light on after I already put oil in the car.

My 2016 Hyundai Sonata with the dohc gdi theta-ii engine is experiencing severe engine oil consumption consistent with Hyundai's known txxi/txxc extended warranty defect. The oil pressure warning has flashed while driving or braking, the engine runs rough when slowing down, engine has made knocking noises, and there is smoke/vapor with a burnt oil smell when removing the oil cap after driving. The oil level drops rapidly between changes despite proper maintenance. This issue poses a risk of engine failure, stalling, or fire while driving. I have maintained the vehicle on time with all oil change receipts. A Hyundai dealership refused to perform the required warranty diagnostics even though this issue falls under Hyundai's extended warranty for theta-ii engines. This is a serious safety concern, and no corrective action has been taken.

The vehicle is going through oil very quicky. No leaks no burning.

The vehicle experienced an engine and power train failure while driving on the highway, resulting in sudden loss of power. The electrical system also failed after the dealer visit, causing the battery to die every morning. Yes, the vehicle is available for inspection upon request. My car suddenly lost power on the highway and would not accelerate, forcing me to pull over on the shoulder with traffic moving around me. This created a serious risk of a rear-end collision or crash. Additionally, after the dealer visit, the electrical system began failing and the vehicle has been completely dead every morning, leaving me stranded with a child and unable to reliably start the car. The problem has not been reproduced because the check engine code cleared itself after the incident; however, the symptoms absolutely remain. The dealer refused to diagnose the loss-of-power event because the code was cleared, and they returned the vehicle to me with a dead battery. The electrical issue (car dying every morning) has been happening consistently since the dealer visit. The vehicle was taken to a Hyundai dealership immediately after the incident, but they refused to diagnose the loss of power due to the code being cleared. A mobile mechanic scanned the code at my home before the tow, but the code disappeared afterward. The electrical failure began after the dealer visit and has not been properly inspected by Hyundai. Yes. While driving on the highway, the check engine light came on and the car immediately lost power and would not accelerate. After the dealer visit, the car has been completely dead every morning and requires a jump to start. These symptoms began on the same day as the highway incident and continued after Hyundai serviced the vehicle.

While driving my 2017 Hyundai Sonata, the engine suddenly began making a loud knocking noise and the vehicle entered "limp mode" the check engine light was blinking, I took the car to a very close autozone and the check engine light came on with code p1326 (pricture upload files), which is directly related to the known ksds connecting rod bearing defect. This issue is part of Hyundai’s safety recalls and engine warranty extensions. After that, I called Hyundai directly (reference number for that call #xxx). A kind young woman informed me that my car had been through "service campaign 953" and successfully completed a "knock sensor detection system (ksds) software update. " thanks to this, she explained that my car is under the "Hyundai txxi warranty" and that, given the noise I was hearing along with the "p1326" code, it was very likely that my car qualified for a free engine replacement. She then scheduled an appointment for me at the nearest Hyundai dealership for the following morning. After more than two weeks of inspection, the dealer confirmed that the engine has internal damage and needs a complete replacement due to rod bearing failure. This is the exact defect addressed in Hyundai’s safety campaigns. However, Hyundai corporate is refusing to cover the engine replacement because the vehicle exceeded its mileage limit, even though the engine failure is clearly caused by the known safety-related defect. The dealer acknowledged the problem and documented everything, but Hyundai is denying proper safety recall-related coverage. This puts my safety and the safety of others at risk, the vehicle is currently disabled and undrivable at the dealership due to the defect. Hyundai is only offering a buyback or a small cash settlement instead of performing the necessary safety repair. I am filing this complaint for many reasons but mainly because the refusal to replace the defective engine, despite the recall-related code p1326 and confirmed bearing failure. Information redacted pursuant to the freedom of infor.

I am the original owner of a 2017 Hyundai Sonata with the oil consumption defect Hyundai is well aware of. For years I have been adding a quart of oil every thousand miles and had my spark plugs replaced three times in two years now. Why am I not included in the recall so I can have the repairs done free of charge? the dealer wanted me to start having them monitor my oil consumption first which will cost me around seven hundred dollars for something they already know is defective. I submitted repair bills for the spark plugs to Hyundai around a year ago, but they would not reimburse. This is a safety issue as car starts to run badly with fouled plugs.

Engine issue - but no recalls there have been hundreds of this same car yr and model with engine issues out of the blue.

My engine recently seized on my vehicle and Hyundai is refusing to replace my engine. Per their website my vehicles engine has a lifetime warranty. This warranty is eligible for class vehicles who have has to campaign 953 reformed on their vehicles prior to engine failure. This was performed in n my vehicle on April 16, 2019. Per Hyundai’s website. I am being offered a settlement I did not take part in instead of my engine replacement and it should be illegal for them to go against their own word.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at an undisclosed speed and making a left turn, the vehicle experienced a loss of motive power. The contact was able to restart the vehicle; however, an abnormal knocking sound was heard, and there was smoke coming from under the hood. The contact was able to drive the vehicle to a nearby residence, where it temporarily remained. The contact attempted to drive the vehicle a few miles to qualify for towing, per the vehicle insurance provider. The vehicle was towed to a local dealer, where it was diagnosed with a rod bearing failure. The vehicle was not repaired due to insufficient engine oil maintenance records. The contact related the failure to NHTSA campaign number: 20v746000 (engine). The manufacturer was made aware of the failure. The failure mileage was approximately 137,600.

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The vehicle experiences a recurring defect where the brake light turns on suddenly and the engine shuts off while driving. The failure appears related to the braking system (brake switch circuit), electrical system (can-bus/ecu communication), and engine control (shutdown/stall). The system remains installed and is available for inspection upon request. The shutdown poses a serious safety risk, including possible rear-end collision or loss of power in traffic. The problem has occurred multiple times. The dealership inspected the vehicle briefly but failed to diagnose or document the defect and returned the vehicle within hours, stating “it shouldn’t be a problem,” even though the issue continues. Hyundai has refused to provide recall documentation or authorize a re-inspection. The only warnings prior to shutoff are the sudden activation of the brake warning light just before the engine cuts off.

Vehicle is putting out a very strong gasoline odor, especially when sitting idle. I looked up previous recalls on the vehicle and seen where there was a recall I believe in 2022 for similar issues.

While driving, my 2016 Hyundai Sonata’s engine suddenly started knocking loudly. I stopped immediately and found the engine oil was very low without any prior warning. After adding oil, the engine still runs but with possible internal damage. This could have caused the engine to seize while driving. There were no warning lights or leaks before this happened.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the engine started to overheat, with the check engine and temperature warning lights illuminated. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 184,000.

The contact's daughter owns a 2013 Hyundai Sonata. The contact stated that the vehicle failed to start. The contact's daughter replaced the battery. A mechanic was able to restart the vehicle; however, the engine made an abnormal knocking sound. The vehicle was not diagnosed or repaired. The contact related the failure to NHTSA campaign number: 17v226000 (engine and engine cooling) for which the VIN was included. The dealer and the manufacturer were not contacted. The failure mileage was approximately 95,000.

I have just purchased this vehicle from jones Nissan in savannah, TN September 27, 2025 for my daughter's 18th birthday. I was told the car passed all inspections etc and was sold the car same day. We checked the oil before leaving and oil was good. Within 45 miles we came home and my husband checked the car and the oil was down half quart. We didn't think anything of it and he did complete oil change. Last night my daughter comes in and my husband checks her oil almost 3 quarts low. There are no leaks nothing we can find. This is absolutely absurd this was a car for my 18-yr old daughter to go to college and back. There are no lights that come on to tell you it is low or nothing. This is completely uncalled for and Hyundai needs to replace or correct this issue. This could cause her to be stranded or hurt if this motor was to lock up.

On the highway, my 2015 Hyundai Sonata suddenly began making a squealing or metallic rattling noise. At first, I thought it might have been something loose inside the vehicle. Within moments, the check engine light began blinking, followed by several additional warning lights and a pronounced knocking noise from the engine area. Immediately after the warning lights appeared, the vehicle entered a reduced-power “limp mode” and began rapidly losing speed, even though the engine was still running. Because this occurred at highway speed while surrounding traffic was traveling normally, I had to pull onto the shoulder to avoid being struck. This created a significant safety hazard. I was stranded for approximately 45 minutes on the shoulder, at risk of being struck by other vehicles passing at high speeds. A tow truck arrived before the highway patrol, and the vehicle was towed home. When I returned home, my code reader pulled two versions of diagnostic code p1326, which is associated with potential engine bearing failure in Hyundai theta ii engines. The issue has since been inspected by the dealership, who confirmed the presence of the p1326 code. The vehicle is currently available for further inspection upon request. There were no prior symptoms that I was aware of leading up to the incident other than the brief squealing/rattling noise and the sudden warning lights immediately beforehand. The failure happened suddenly and without warning, causing an immediate and unexpected loss of speed and creating a dangerous situation on the highway.

Engine failed on 10/24/2025. Hyundai will not honor class action suit to repair engine at no cost to owner. Hyundai state recalls were not completed on the car prior to engine failure. We agree, recalls were not completed prior to failure. Because we never received notification. Had we received notification we would have acted on the recalls immediately and not put our safety, that of our children or the general public at risk by driving a vehicle with an engine that could fail at any moment. We have contested Hyundai's rejection several times to no avail. We are seeking guidance in resolving this mater.

I bought this car from someone in April of 2024 and the person who I bought it from said everything was perfectly fine, they brought it to the Hyundai dealership and according to the mechanic there the engine was fine…. I have taken care of the engine since I bought the car, kept up with oil changes and everything…. Until a few days ago when the whole thing ceased up on me while driving down the road to my sons school. I wasnt going fast either, the speed limit is 40mph where I was when it happened, but I’m glad I have quick reflexes because otherwise we would have wrecked the car. Everything shut off on me and now its knocking. There is alot of metal shavings in my oil and my mechanic tried to drain it a few times to get the debris out of the oil but it does no good.