2018 Hyundai Sonata

373 complaints on file, page 1 of 19.

1. Filed Sep 21, 2026Failure Sep 21, 2026Decatur, ILEngine

   Hyundai dealership confirms I am in need of a new engine due to large oil consumption which is a known issue on 2018 Hyundai Sonata engines. Hyundai will not approve repairs because I am the second owner and vehicle is out of the 5 year warranty period. I only have 52K miles on my vehicle.

   NHTSA complaint 11765780
2. Filed Sep 11, 2026Failure Sep 9, 2026Albion, PAEngine

   One engine valve has lost pressure and is not repairable

   NHTSA complaint 11763562
3. Filed Sep 8, 2026Failure Feb 1, 2026Virginia Beach, VASuspension

   Vehicle has been making a clunking noise (front passenger area). Brought to independent service center where they determined that the strut tower is failing. Current mileage 66000. Appt set for Checkered Flag Hyundai to evaluate on 9/11/2026.

   NHTSA complaint 11762770
4. Filed Sep 4, 2026Failure Sep 3, 2026Rockwall, TXFuel/propulsion system

   My car stalls while driving and then I try to restart it but nothing happens. After reading online about the fuel pump issues and extended warranty related to the fuel pump I took the car in for repair. My car has 75,000 miles and the extended repair on this is for 150,000 miles/15 years. The dealer is refusing the repair because my car has a branded/ theft title. The car wasn't damaged just stolen. This is creating a serious safety concern and should be repaired by the dealer. Thank you for your time.

   NHTSA complaint 11762281
5. Filed Aug 25, 2026Failure Jul 17, 2026Clemmons, NCEngine

   Since I had Service Campaign 9C2 completed, the car hesitates to start, does a mini-lurch upon cold start and runs rough. Two weeks ago, it was put in park, lurched backwards, then died. The starter and battery have been replaced but this has not helped. The car ran fine before this update was done.

   NHTSA complaint 11759477
6. Filed Aug 16, 2026Failure Jul 15, 2022Raleigh, NCEngine, Body

   The paint on all parts of the car is completely coming off down to bare metal. It’s as if the car wasn’t prepped to receive paint. Every Hyundai I pass that’s white the paint is coming off. There is also an internal engine oil leak where I’m losing 4qts of oil a week.

   NHTSA complaint 11757263
7. Filed Aug 16, 2026Failure Jul 14, 2026Richardson, TXEngine, Power train

   I recently had the 9C2 Emissions recall update performed on my car, and since the update my car drives like total garbage after a cold start. It hesitates to accelerate, it bucks when trying to accelerate, and it’s to the point the engine is about to stall. I took it back to the Hyundai dealership and they said they are aware of the issue, but there is no fix from Hyundai at this time. This is a major safety concern, as the car barely wants to accelerate after a cold start. Please have Hyundai fix this safety issue.

   NHTSA complaint 11757253
8. Filed Jul 24, 2026Failure May 11, 202692,000 milesWalls, MSFuel system, Gasoline

   The contact owns a 2018 Hyundai Sonata. The contact stated that while operating the vehicle, there was an abnormal fuel odor inside the vehicle. The vehicle was taken to the local dealer and was diagnosed with an inoperable low-pressure fuel pump. The contact was informed that the low-pressure fuel pump needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure. The contact stated that the manufacturer had issued an extended warranty coverage for the failure. The failure mileage was 92,000.

   NHTSA complaint 11752670
9. Filed Jul 20, 2026Failure Jul 13, 2026Little Elm, TXEngine

   The lower aluminum engine oil pan developed a structural hairline fracture ("micro-crack") directly along the factory casting ridge adjacent to the drain plug. The component failed without any external impact, road hazard, scraping, or underbody damage. The failure was officially confirmed and documented by Eckert Hyundai during a service visit on July 13, 2026 (Case #42971835). Following the dealer oil service, the fracture degraded into an active, worsening oil drip that requires a catch tray under the vehicle to capture leaking fluid. The vehicle is currently available for inspection. Safety Risk: An active engine oil leak poses a significant safety hazard. Rapid or continuous loss of engine oil can cause sudden oil starvation, severe engine seizure, or total power loss without warning while driving at highway speeds, increasing the risk of a crash. Furthermore, dripping oil contacting hot exhaust or engine components presents a potential fire hazard. Prior Symptoms / History: This vehicle has a well-documented history of severe internal engine issues and thermal stress, including excessive oil consumption (running 1.2 quarts low in 1,127 miles), valve cover gasket failure, and severe drivetrain vibrations from failing front axles. The excessive internal crankcase pressure and thermal stress from these underlying defects contributed directly to the material fatigue and structural failure of this aluminum oil pan.

   NHTSA complaint 11751641
10. Filed Jul 8, 2026Failure Jul 7, 2026Makawao, HIFuel/propulsion system

    Fuel line leak, car is parked, fire hazard, a mechanic has been there to inspect

    NHTSA complaint 11749020
11. Filed Jul 6, 2026Failure Jun 9, 2026Warren, OHEngine

    I purchased my vehical at Car Culture in Warren, Oh. The dealer said to only take it there for maintenance, so I did as required. Whenever the check engine light came on I would bring it there and they would say it was a sensor and they fixed it. And one day it started miss firing and the light came on again. When I took it to the dealership, they said it needed oil to bring it in every 2 weeks to top the oil off. And so I did that and finally the car was getting worse at 122,000 miles. When I took it there they said it needed a new motor!!!. They NEVER told me of a recall or a sensor replacement needing done by hyundai. Iam now stuck with a $13,000 loan on a car worth nothing without paying $5,000 on a "possible" fix for their negligence. I have a [XXX] old son, fiancee, morgage and a job im struggling to get to, because I was never notified of a possible recall on my year, make and model of car. Please help me. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

    NHTSA complaint 11748511
12. Filed Jun 19, 2026Failure Jul 10, 2025Lindenwold, NJEngineFire

    Vehicle caught fire after repeatedly taking it to Hyundai for service . I complained about the oil consumption and knocking noises while the vehicle was still under warranty and it was denied.

    NHTSA complaint 11745212
13. Filed Jun 16, 2026Failure Jun 14, 2026Hilliard, OHEngine, Power train

    Check engine light solid/engine failure while driving. 2018 Sonata SE purchased new in fall 2018. Around 50,000 miles started noticing oil level drop and had to add more before next scheduled change. Dealership service center said I just had to shorten the mileage between changes which didn't seem appropriate for a vehicle with 50,000 miles but I did. Continued to have oil consumption problem with no signs of leak, no burning oil smell or exhaust issues. Dashboard display would go off and when I immediately checked dipstick there was barely any oil so I'd add more then go in for full change. At 67,000 or so miles in June 2026, without oil display going off the engine light was now solid. Got to reputable service center near my home and oil was under a quart left yet the warning lamp hadn't gone off. They ran the engine error code P0304 and was misfire #4 cylinder and after compression test, #3 was very low and #4 very high. NOT drivable at that point then towed to dealership so yes, available for inspection by NHTSA at the dealership. For now they claim a 'tune up' is needed for spark plug replacement, valve cover gasket replace and fuel induction service that's my cost to incur which seems to just be fixing the damage of an engine oil consumption problem not fixing the issue that caused the damage. The engine seized/stalled without warning while I was driving the vehicle (granted at low speed in my neighborhood when the engine light turned on). I would not say the engine warning lamp occurred prior to the engine fail, it happed at the same time. This should not happen for a vehicle with my mileage and regular maintenance. I looked up NHTSA for potential recall or other helpful information and started to see extremely similar scenarios to mine and wanted to add complaint as well. This is getting very expensive outside of whatever cost the dealer wants as a fix with rental car needed and tow services. Thank you for your consideration of this engine safety issue.

    NHTSA complaint 11744559
14. Filed Jun 13, 2026Failure Jun 9, 2026Conroe, TXUnknown or other

    I was only in the car for about 4 minutes then came to a stop light. Once the light had turned green I pressured down on the gas, my car rolled for a second then died on me, causing it to go into accessory mode. Instantly three lights came on: the check engine light, battery light, and low oil light. The car would take at least 5 seconds to turn back on then would fall back into accessory mode randomly. Tried to jump the car 4 times, issue still remains. What sucks about this is that the mechanic shop can’t even figure out what’s wrong. They thought it was the high pressure fuel pump..turns out it’s not.

    NHTSA complaint 11743841
15. Filed Jun 11, 2026Failure Mar 14, 2026Northbrook, ILEngine, Power train

    Following completion of Service Campaign 9C2 (ECU software update, TSB 25-01-087H) at a Hyundai dealership, my 2018 Sonata immediately exhibited drivability changes that were not present before the service. Symptoms include altered shift timing, hesitation, and rougher throttle response — particularly noticeable during the first several minutes of driving. These symptoms began on the first drive after the recall update was applied and have been consistent since. The vehicle was returned to the dealership for inspection. No underlying mechanical issue was found, confirming the drivability change is directly attributable to the ECU software update. The vehicle has been maintained strictly per Hyundai's manufacturer-recommended schedule and had no prior drivability issues. I am aware that numerous other owners of Theta II-equipped vehicles (Sonata, Santa Fe, Tucson) have reported identical symptoms following 9C2. At least one dealership has reportedly acknowledged this as a known post-update issue that Hyundai is working to resolve. The altered throttle and shift behavior poses a safety concern, as unexpected hesitation during acceleration affects predictable vehicle control in traffic. The vehicle is available for inspection upon request.

    NHTSA complaint 11743622
16. Filed May 26, 2026Failure May 14, 202647,575 milesCenterville, ILEngine, Power train

    The contact The contact stated that when taken the vehicle for a service campaign repair and shortly after went for recall r The vehicle does not run properly on cold starts, the RPMs increase rapidly and slow down, vehicle jerks forward once beginning to drive.. The vehicle does not have this issue once the vehicle is warm. The manufacturer was not notified of the issue. The approximate. Failure mileage was 47,575.

    NHTSA complaint 11740030
17. Filed May 12, 2026Failure Apr 4, 2026Sacramento, CAEngine, Fuel/propulsion system, Power train

    Engine blown out malfunction took two dealer Hyundai Folsom Lake stated rings are bad sludge buildup in engine and stayed at Hyundai motor America denied engine replacement due to knowledge under Theta two engine extended warranty settlement of 150,000 MI 15 years I'm still within warranty but are still being denied had numerous of issues with vehicle oil consumption knock knock sensor replace and other maintenance done since purchase vehicle brand new in 2018

    NHTSA complaint 11737468
18. Filed May 6, 2026Failure Sep 23, 2024League City, TXEngine, Fuel/propulsion system

    I am submitting this complaint to report a serious and ongoing safety defect involving the engine of my 2018 Hyundai Sonata Sport equipped with the 2.4L Theta II engine. The vehicle has been officially tested and documented by Hyundai as consuming more than two (2) quarts of engine oil per 1,000 miles, which Hyundai has acknowledged following completion of its oil consumption test procedure. Despite this confirmation, Hyundai has declined to fully correct the defect. As the condition has progressed, the engine now fouls spark plugs every 350–500 miles, resulting in: •Engine misfires •Loss of power during operation •Rough running and hesitation •Risk of sudden engine stalls while driving This condition occurs without warning and requires repeated roadside or emergency repairs simply to keep the vehicle operable. The condition has deteriorated further, requiring replacement of fouled spark plugs every 350-500 miles. Loss of power and engine shaking can occur at any time, presenting a safety hazard for me and other drivers.

    NHTSA complaint 11736185
19. Filed May 5, 2026Failure Nov 1, 2025Pearidge, AREngine

    Despite proper maintenance, the vehicle is burning oil at an excessive rate. I have already replaced the oil pan, but the issue persists. I now have to add oil frequently between oil changes. This creates a serious safety concern, as low oil levels can cause engine failure while driving, leading to sudden loss of power or stalling in traffic. This puts me, my passengers, and other drivers at risk. There are no visible leaks, which suggests the oil is being burned internally. This appears to be a potential defect rather than normal wear and tear. I am requesting that this issue be investigated as it may affect other vehicles of the same make and model. This is becoming very expensive having to refill oil as the dipstick shows nothing. This has been confirmed by technicians that there has been no oil in my car despite coming in on time or before the recommended miles. The oil light will come on a few weeks after having the oil changed. It seems this is an issue with this engine type.

    NHTSA complaint 11735867
20. Filed Apr 27, 2026Failure Apr 27, 2026Ontario, CABody

    The trunk latch on the Hyundai Sonata malfunctioned, and our safety was put at risk when the trunk malfunctioned while driving on the freeway, obstructing the back view. After several attempts to try to close the trunk and after doing some research, I learned it had a vehicle recall, 21V619000. An appointment was made at Ontario Hyundai for the latch to be repaired due to the recall. After taking the vehicle in, the dealer stated that an attempt to repair the latch had been attempted and refused to do the repair and provided an invoice of $616.00 for repair. Since the latch malfunctioned, no attempt to repair the latch was ever attempted, nor was it taken anywhere else for repair. The vehicle is available for inspection upon request. The trunk latch is still inoperable, and recall status is incomplete.

    NHTSA complaint 11734172