Hyundai Sonata Complaints (2018)

384 consumer complaints on file.

#11686389September 10, 2025
ENGINE
Summary of the Problem: My 2018 Hyundai Sonata has a serious engine defect related to excessive oil consumption. Despite proper maintenance, the vehicle consumes large amounts of oil between service intervals. This has caused the engine to seize and the car’s software to restrict speed to 40 mph while driving, creating a dangerous situation on public roads. Details: Vehicle purchased from an authorized Hyundai dealer in Massachusetts (second owner). Issue first identified around 65,000 miles. Inspected multiple times at Stevens Creek Hyundai (San Jose, CA). Service center confirmed this is a known internal engine issue but refused to replace or repair unless the engine completely fails. I was told to “keep topping up oil,” which is not a safe or permanent solution. Safety Concern: Sudden engine seizure or restricted speed while driving could result in an accident, especially on highways. This defect places me and my family at serious risk of injury or death. Requested Action: I urge NHTSA to investigate Hyundai’s handling of this engine defect and require Hyundai to repair or replace affected engines before they fail, regardless of ownership status. Consumers should not have to wait for catastrophic engine failure to receive assistance.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685678September 8, 2025
ENGINE
Purchased a 2018 Sonata Sport in 2022 not knowing oil consumption was an issue. After noticing that my oil was low after I would get an oil change made me very suspicious. Drove to a Hyundai Service Center and paid out of pocket for a diagnostic. Was told cracked oil pan but they never performed any of the standard diagnostics for the high oil consumption. We ordered the oil pan and scheduled service, told we were good to drive & still till this day of 9/5/2025 I'm still putting oil in my car because it just burns through it. I am scared that this car leaves me on the side on the road with my kids. Also when I bought the car in march 29 2022 that car has given me nothing but problems with oil consumption, non stop spark plugs replaced & knocking. I have a video of the knocking & I’ve even asked Hyundai when I brought it in they couldn’t find the issue. They even ran dye through my engine to see if it had any leaks & it had none. So where is the oil going & why is my engine knocking?
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685382September 5, 2025
ENGINE
Purchased a 2028 Sonata Sport in 2022 not knowing oil consumption was an issue. After noticing that my oil was low after I would get an oil change made me very suspicious. Drove to a Hyundai Service Center and paid out of pocket for a diagnostic. Was told cracked oil pan but they never performed any of the standard diagnostics for the high oil consumption. We ordered the oil pan and scheduled service, told we were good to drive & still till this day of 9/5/2025 I’m still putting oil in my car because it just burns through it. I am scared that this car leaves me on the side on the road with my kids.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11683921August 29, 2025
EXTERIOR LIGHTING
Back up lights. The lights constantly burn out causing the harness light holder to burn out. The lights will not come on even after replacing fuse and lights There are not back lights to warn patrons on the road for turning or stopping Yes it was taken to a dealership No it has not been inspected my either , but there is a recall on models of the same car but years 2011-2014 No there were no warnings , someone told me they were out
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11683957August 29, 2025
ENGINE
The contact owns a 2018 Hyundai Sonata. The contact stated that while driving approximately 60 MPH, the vehicle shuddered before losing automotive power. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed and determined that the engine and NOx sensor needed to be replaced. The vehicle was repaired; however, the failure reoccurred. The vehicle was taken back to the same local dealer on several occasions for the repair; however, the failure reoccurred. The manufacturer was not made aware of the failure. The failure mileage was approximately 117,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11682710August 24, 2025
ENGINE
My 2018 Sonata has had an oil consumption problem since 2023. We initially thought it was the oil change garage issues. Had an oil consumption study conducted by Hyundai between July -September 2024. We were replacing 1,0 -1.5 qt oil every 700 - 1,300 miles. After the study, Hyundai told me I did not have an oil consumption problem. (Seriously?!?!) We had to replace the starter and now the spark plugs. Photo enclosed of how burnt the spark plugs were. Our mechanic was so mad that Hyundai was not honoring their warranty but allowing my engine and connected parts to just burn up. Hyundai told me to come in for another check tomorrow, 8/25/25. I called the Hyundai Consumer line on 8/18/25 (4th new case number in 13 months) and the person who answered the phone asked if I contacted a lawyer. I asked her if I needed to contact a ? I’ve been reading online about this problem today and found information about NHTSA and decided to file a complaint. This is dangerous because when the engine blows, I may be accelerating on the interstate and merging. That could be a fatal problem with this car. Traveling on the interstate on 8/10/2025 my Sonata stuttered and hesitated upon acceleration. We took back roads and limped home. My mechanic replaced the severely burnt spark plugs and told us our very nice car would be worthless soon if Hyundai did not fix this oil consumption problem. He called our Hyundai dealer on our behalf.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11681369August 18, 2025
ENGINE, ELECTRICAL SYSTEM
I first noticed that my vehicle was consuming an excessive amount of motor oil, with the oil change light coming on every 1,500–2,000 miles. I routinely had to add oil between changes to keep it running. On May 30th, while driving on surface roads, I heard clanking noises from the engine. When accelerating, the vehicle clanked heavily, and then went into “limp mode,” limiting acceleration to about 10 MPH before struggling up to 30 MPH. I added oil, but a local shop diagnosed it with code P1326 (knock sensor) and advised that Hyundai engines are prone to failure around 100,000 miles and that I should take it to the dealer for warranty evaluation. I contacted Graham Hyundai, who told me they could not see the vehicle until July 1st and that I would be responsible for towing. I dropped the vehicle off on July 1st, but it was not inspected until July 8th or 9th. I was later told Hyundai was being consulted. Around July 15th–16th, the dealership informed me that I would need $1,500 in repairs. They stated the engine had passed the Hyundai Bearing Clearance Test (a $350 charge) and that Hyundai required me to pay for an ECU “KSD logic” upgrade ($175). They also stated the engine valve cover was leaking, requiring new spark plugs, for a total of $532. Additional charges included an oil change and other shop fees and taxes. After repairs, I was instructed to drive 1,000 miles and then return for an oil consumption test. After approximately 1,000 miles and four weeks, the dipstick check showed the vehicle had consumed nearly all of its oil. I was then told I now need a combustion chamber cleaning, costing approximately $850 and requiring three days in the shop. Given the oil consumption issues, repeated engine warnings, limp mode incident, and the significant costs already incurred for testing and required upgrades, I am requesting that my engine be replaced under warranty and that all fees I have already paid be reimbursed. Rather than keep paying for work.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11681198August 17, 2025
STRUCTURE:BODY
The paint has been chipping from the hood and top.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11681116August 16, 2025
FORWARD COLLISION AVOIDANCE: WARNINGS, SERVICE BRAKES
About a year and half ago, a lot of my engine trouble lights turned on while driving. It was sleeting at that time when the lights turned on and they're still on today. I paid to have the Hyundai dealer to check it out soon after the trouble lights first turned on. They diagnosed the problem as a faulty HECU. I would have had them replace this, but they estimated it would cost about $3800 to fix. This HECU malfunction is causing the following issues: ABS does not work, traction control does not work, forward collision prevention does not work, brake auto hold does not work, cruise control does not work probably because it can't auto brake any more. I've had some scary times driving and trying to stop when the roads have been wet or snowy.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11680962August 15, 2025
ENGINE
Component or system that failed or malfunctioned: The 2.4L Theta II engine in my 2018 Hyundai Sonata is consuming an excessive and unsafe amount of engine oil—approximately 1 quart every 750–1000 miles. The engine has not seized or failed yet, but the oil consumption is abnormal and dangerous. The engine is available for inspection upon request. Safety risk: This oil consumption issue poses a significant safety risk. If the engine runs out of oil unexpectedly, it could lead to catastrophic engine failure and sudden loss of power while driving—potentially causing a serious accident. The lack of warning or engine light prior to dangerously low oil levels increases the risk. Reproduction/confirmation: The issue has been reproduced and documented by a certified Hyundai dealer through an oil consumption test. However, despite confirming the problem, Hyundai has refused to cover the repair. Inspection history: The vehicle has been inspected by a Hyundai dealership. No other independent agencies (e.g., insurance or police) have inspected it. Warning lamps or messages: No warning lamps appeared before the engine oil was found to be dangerously low. There were no check engine lights or oil pressure warnings prior to discovering the oil consumption issue. Other key information: Hyundai refuses to cover the repair due to the fact that I am not the original owner—even though the original Powertrain warranty would have covered the issue if I were. Hyundai arbitrarily reduces the powertrain warranty to 5 years/60,000 miles for secondary owners, despite the safety risks being identical regardless of ownership. Furthermore, this exact engine has been the subject of multiple lawsuits and class actions due to excessive oil consumption, connecting rod bearing failure, and engine seizure. Hyundai has acknowledged the defect in various settlements but continues to deny coverage for affected owners like me.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11679941August 11, 2025
ENGINE, POWER TRAIN
Engine failure. Definitely a safety issue, check engine light flashing, limited engine power. Wouldn’t accelerate. Dealer inspected, there is a nationwide recall and class action lawsuits and they won’t replace even though it’s under warranty. False information saying maintenance neglect on my part. That is FALSE. Known failure and oil consumption. Rod bearing failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11679047August 7, 2025
ENGINE
My car is consuming oil. Hyundai knows this is happening with the theta II engines. I was told to bring it in and do an oil consumption test which shows my car is consuming 1 qt oil every 406 miles but was denied help due to it being high Mileage and not under warranty. My car has now started misfiring due to cylinder 1 & 2 consuming oil.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11679080August 7, 2025
FUEL/PROPULSION SYSTEM
The fuel pump filter housing is the cause of the malfunction, it is available for inspection upon request. When I am driving I intermittently lose fuel delivery altogether and my car comes to a halt for a second until I press on the gas pedal to get the car going again, this puts myself and other people in danger if my car randomly stops while I am driving around others and causes crash risk. An independent service center ran a diagnostic and stated it was the fuel pump filter housing. It has not been inspected by the manufacturer, police, or insurance reps. But it has been inspected by the service center near me. An engine code was produced that pointed to the gas cap, but the gas cap was fine, which indicates fuel delivery issues. There was also shaking during acceleration prior to the incident happening. My VIN does not fall under the current extended warranty, but the issues are identical to the issues of the VINs that do fall under the extended warranty.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11679114August 7, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2018 Hyundai Sonata. The contact stated that after starting the vehicle, the engine oil warning light illuminated intermittently. The contact pulled over to check the engine oil level and discovered that there was no oil in the engine. The vehicle was taken to Midas, and engine oil was added. The vehicle was later taken to another Midas, who found a crack in the engine oil pan. The vehicle was then taken to the dealer, who informed the contact that Midas had overtightened the oil pan during an oil change, so the warranty to repair the vehicle would not be honored. The vehicle was taken back to Midas, and the engine oil pan was replaced. The contact stated that he was currently in litigation with the dealer and the manufacturer. The manufacturer was made aware of the failure. The failure mileage was approximately 99,000. The VIN was unavailable.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678903August 6, 2025
ENGINE, FUEL/PROPULSION SYSTEM
Urgent Complaint About Repeated Engine Issues on 2018 Hyundai Sonata (VIN: [XXX] ) Hello, I’m writing to file a formal complaint regarding a 2018 Hyundai Sonata, VIN [XXX] , currently financed and still owing $9,700, but the vehicle is no longer reliable or functional. For over a year, the car has had constant mechanical issues, primarily: •Spark plug failures within weeks of replacement •Repeated misfiring •Constant oil consumption — requiring oil refills every few days •No clear cause ever detected by diagnostic machines Despite replacing the top engine cover, spark plugs, filters, and performing other repairs, the car continues to break down and remains unsafe to drive. These issues began shortly after the 2-year warranty expired in 2023, and have escalated rapidly. This has caused severe financial hardship for my family, who still have to pay nearly $10,000 on a loan for a failing vehicle. I am requesting Hyundai to investigate whether this vehicle qualifies for: •An engine recall, hidden warranty, or class action settlement •A buyback or goodwill repair INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678701August 6, 2025
FUEL SYSTEM, GASOLINE, ENGINE AND ENGINE COOLING, POWER TRAIN
The contact owned a 2018 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the vehicle sputtered, jerked, and lost motive power. The check engine warning light was illuminated. The vehicle was able to restart but made an abnormal ticking sound. The vehicle was taken to the dealer but was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 72,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678065August 3, 2025
ELECTRICAL SYSTEM, ENGINE
car turned off at light all lights work and turns on engine won’t roll over the battery and alternator and starter are all good
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678101August 3, 2025
ENGINE
Burning a lot of oil had car 11 months only drove a few month,now it’s a tapping sound dealer where i purchase will not help nor will Hyundai dealer 15,000$ out the window now I need to get the lifters fix I can’t take it. I feel like I’ve been had. Now I got to figure to fix the car out of pocket however o haven’t had the car 1 year yet 81,000 miles.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11677493July 31, 2025
UNKNOWN OR OTHER
My starter failed after 35,683 miles leaving me stranded in a parking lot at night. The life expectancy for a starter is between 100,000and 150,000 miles. Hyundai replaced the part at a cost of $1,139 which is way above what it normally costs to replace a starter. The starter is at the dealership and is not available for inspection. Being stranded in a parking lot made me very uncomfortable and what if the starter had failed in a bad section of town. The problem was confirmed by a Hyundai dealership who replaced the part after I had my vehicle towed to their service department. The only ones who inspected the vehicle was a mechanic at the dealership. There wer no warning lamps or messages, but I did notice the car did not start on the first try before the starter failed. 07/29/2025
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11677632July 31, 2025
ENGINE, EXTERIOR LIGHTING, UNKNOWN OR OTHER
Check engine light keeps coming on got it looked at , certain parts replaced & it’s still on something to do with the air filter
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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