Complaint volume
358 consumer-submitted complaints are matched to this model year. Treat the count as a research signal, then read the actual summaries for repeated symptoms.
Complaint records
2018 Hyundai Sonata Complaints
358 consumer-submitted complaints on record for the 2018 Hyundai Sonata, grouped by component category.
358 Total complaints
18 Crash reports
12 Fire reports
9 Injury reports
Complaint data reflects consumer-submitted reports. A complaint is not proof
of a defect, recall, or manufacturer fault. Enriched severity fields come
from official bulk records when the complaint can be matched by ODI number.
Buyer interpretation
How to use these complaints before buying
Complaint records are most useful when they turn into inspection points, seller questions, and comparison checks against nearby model years.
Pattern to inspect
The most common categories are engine, unknown or other, electrical system,engine. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 18 crash reports, 12 fire reports, 9 injury reports, and 1 fatality report. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 135 complaints, with an average reported failure mileage of 37,255 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to engine, unknown or other, electrical system,engine?
- Can I see recent maintenance and repair records?
- Has the vehicle ever been towed, involved in a crash, or repaired for the same issue twice?
- Can we also check the recall record for this 2018 Hyundai Sonata?
Used-car checklist
Use these complaints before the test drive.
Build a buyer checklist to turn these issues into questions and inspection points.
2018 Hyundai Sonata
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2018 Hyundai Sonata complaints?
18 Crash
12 Fire
9 Injury
1 Fatality
28 Towed
6 Medical attention
What are the most common 2018 Hyundai Sonata complaint categories?
ENGINE 113
UNKNOWN OR OTHER 32
ELECTRICAL SYSTEM,ENGINE 15
EXTERIOR LIGHTING 15
ENGINE AND ENGINE COOLING 11
STRUCTURE 11
ENGINE,FUEL/PROPULSION SYSTEM 8
POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM 8
ELECTRICAL SYSTEM 7
ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM 7
358 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Jun 2025 | ENGINE | Failure of engine oil pan. - Hairline crack in oil pan caused enough oil to leak out threatening engine failure. Problem caught in time to avert failure. - Oil pan will be available if requested. - Personal safety not at risk but could have been if failure occurred while driving. - Problem was discovered and confirmed at by independent service center. - No inspection has been done by others. - YouTube and internet search shows same problem. - No warning warning signs or messages. - Problem not covered by manufactures warranty for second owner. | Crash: No Fire: No | Unknown |
| Jun 2025 | UNKNOWN OR OTHER,ENGINE,FUEL/PROPULSION SYSTEM | Multiple critical mechanical and safety issues have occurred with my 2018 Hyundai Sonata Sport. The vehicle has experienced persistent engine misfire, a severe oil leak, emissions system failure, and extensive paint deterioration. A certified technician confirmed an active oil pan leak with no dashboard warning lights, posing a fire and stalling hazard. To prevent further damage, I replaced the entire oil pan and spark plugs at a personal cost of approximately $800 at Firestone Complete Auto Care. The check engine light revealed diagnostic code P0420 – Catalyst System Efficiency Below Threshold (Bank 1). An O’Reilly emissions scan confirmed the catalytic converter failure, and emissions status was marked “RED.” The vehicle will not pass an OBD-based emissions test. At 149,219 miles, Hyundai refused warranty coverage due to mileage. A certified Hyundai dealership quoted $3,722 to replace both the catalytic converter and valve cover gasket, which remains unaffordable and unrepaired. In addition, the factory-applied white paint began peeling severely from the hood and roof. Although Hyundai issued a warranty extension for this known defect, the dealership refused to repaint the hood, citing a minor dent — even though the peeling is clearly unrelated. The exposed metal has started to rust, risking structural deterioration. All concerns have been evaluated by certified Hyundai service and independent professionals. These combined mechanical, emissions, and exterior failures raise serious safety and durability concerns. I am filing this report to document manufacturer-related defects that may affect other owners of this model and year. | Crash: No Fire: No | Unknown |
| May 2025 | ENGINE,FUEL/PROPULSION SYSTEM | Burns oil fast. 900 miles from an oil change the car oil stick was empty. There are no signs of oil leaking. Every 1000 miles you have to place oil back into it. I’m not the only one complains of this issue. I was reading on Reddit and it’s thousands of people having the same issue. | Crash: No Fire: No | Unknown |
| May 2025 | SERVICE BRAKES, HYDRAULIC | The contact owns a 2018 Hyundai Sonata. The contact stated that upon starting the vehicle, the ABS warning light illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that the ABS module had failed. The vehicle was not repaired. The dealer was notified of the failure. The manufacturer was not notified of the failure. The failure mileage was approximately 40,000. | Crash: No Fire: No | Unknown |
| May 2025 | ENGINE | CAR STALLS; ENGINE IMPAIRED; OIL CONSUMPTION PROBLEM | Crash: No Fire: No | Unknown |
| May 2025 | ENGINE | I have had to have the starter replaced twice, I have had to change the spark plugs 5 times. I have to put oil in it about every 3 weeks. White smoke comes out of the muffler. The mechanic said I need to have an oil consumption test, which Hyundai will not covet. | Crash: No Fire: No | Unknown |
| May 2025 | ENGINE | I have a 2018 sonata. It has thrown a p1326 code. There is a TSB for that code where the dealership will Check to see if the engine will Be replaced. My car passed that test meaning no engine replacement. My car has 107,000 miles on it and has had regular maintenance. In between oil changes I’m having to add oil. I’m spent hundreds on engine oil since taking owenship of the car. There is obviously an issue with the engine since there is a TSB. Yes my car passed”passed the test this time” (I’m having to pay $600 to replace the knock sensor). I feel like I’m driving a ticking time bomb and money pit. I feel as though Hyundai should handle this known issue. I need help. | Crash: No Fire: No | Unknown |
| May 2025 | UNKNOWN OR OTHER,ENGINE | I have to put a quart of oil in every week. It burns oil. | Crash: No Fire: No | Unknown |
| May 2025 | UNKNOWN OR OTHER | Panoramic sunroof came loose on highway and bent up 90 degrees making vehicle undrivable. | Crash: No Fire: No | Unknown |
| Apr 2025 | ENGINE | This engine consumes oil rapidly to the point i have to add quarts of it constantly . This results in the spark plugs deteriorating at a rapid rate and the coil packs as well. The car only has 75,000 miles but the problems began to start around 69,000 miles because of these issues and the engine and burning oil because of the rings and pressure it begins to shake rapidly and sputter and stall out. | Crash: No Fire: No | Unknown |
| Apr 2025 | POWER TRAIN | The car went into limp mode they have problems with the knock sensor and that is what it threw to the computer and I changed the sensor and went away and now limp mode again and computer says basically the same thing there is a software update and the engines are failing | Crash: No Fire: No | Unknown |
| Apr 2025 | STEERING,POWER TRAIN,ENGINE | The engine stalls when driving, loses power, hard time to start. It uses an extensive amount of oil. Losing power/stalling can result in accident or fire in my engine. Yes check engine light came on said it was coils/plugs changed them 2xs already. Took it to a mechanic was told there’s a recall on engine it’s a valve that is not getting air through that can potentially case a Fire in my engine. | Crash: No Fire: No | Unknown |
| Apr 2025 | ENGINE AND ENGINE COOLING | The contact owns a 2018 Hyundai Sonata. The contact stated that the vehicle needed multiple attempts in order to start. The contact stated that once the vehicle was started, she noticed that the low engine oil pressure light was illuminated. The vehicle was taken to a local dealer, where it was determined that an oil consumption test needed to be completed. The vehicle was not repaired. The contact had stated that prior to the oil test being recommended, she had observed that the vehicle was consuming approximately five quarts of oil per 2,000 miles. The manufacturer was notified of the failure. The failure mileage was approximately 57,000. | Crash: No Fire: No | 57,000 |
| Mar 2025 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | My 2018 Hyundai Sonata (approx. 60,000 miles) began consuming excessive oil, and the engine started smoking while driving. My wife barely made it to the dealership — the car was unsafe, struggled to stay running, and visibly smoked from under the hood. Hyundai acknowledged the oil issue but refused to cover engine replacement. Instead, they approved a one-time combustion chamber cleaning and requested we drive the car 1,000 miles to "see if it gets better." This is a major safety concern. The vehicle is part of a group of Hyundai models known to have defective Theta II engines that have led to engine failure, fire risk, and recalls. This issue is widespread, and Hyundai is not taking proper responsibility for defective engines in cars like mine. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE | The contact owns a 2018 Hyundai Sonata. The contact stated that the oil pressure was prematurely lower. The contact stated that while performing the oil change as an independent mechanic, the contact noticed that there was a significant amount of oil in the oil catcher, and the oil pan was fractured. The vehicle was taken to the dealer, where the contact was informed that the oil pan replacement was not covered under warranty. The vehicle was not repaired. The contact related the failure to NHTSA Action Number: DP22003 (Engine). The manufacturer was notified of the failure and a case was filed. The failure mileage was approximately 64,400. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE | The engine is burning through oil at a rapid rate. I probably get 2,000 - 2,500 miles before it needs a complete refill and the problem is getting worse. I was not due for an oil change recently around 2,500 miles and my engine started shaking, took it to the shop and the oil was gone without the oil light going off. This resulted in me needing to replace spark plugs and all engine coils. The repair shop recommended I sell my car because of the amount of Hyundai's he sees with this issue. | Crash: No Fire: No | Unknown |
| Mar 2025 | STRUCTURE,ENGINE | The engine burns oil, I have to get spark plugs every two months, and put oil in it almost every week. The check engine light is now flashing and is throwing more sensors. The paint on this car is also all peeling off. | Crash: No Fire: No | Unknown |
| Mar 2025 | ENGINE | 2018 Hyundai Sonata Registered owner [XXX] Vin [XXX] Which qualifies for a replacement engine under the "recall" and "class action" due to engine oil consumption damage. On [XXX] I was driving home from California, and my 2018 Hyundai Sonata made a loud noise and stalled on me while driving on the freeway. On Jan 2, 2025 I towed my 2018 Hyundai Sonata to ABC Hyundai for repairs. I was told the engine failed or locked up. I have a drivetran warranty up to 150k. My vehicle currently has 115k. However, Hyundai denied the engine repair stating that I neglected the maintenance on the vehicle. They were requesting oil change receipts from 2018 when I bought the car. I've submitted all oil change documents that I could find. Most auto shops have purged their system, updated their software and also got entirely new systems, therefore those receipts were not found. Carfax also has a record of oil changes. I did not always take my vehicle to the dealer for oil changes since our family has a certified mechanic that can vouch for all the other oil changes done on the vehicle. Including tune-ups. The dealer and I have provided several oil change receipts approx. 18+ carfax, Hyundai, family mechanic and misc. receipts. That's should be more than enough evidence for Hyundai to honor their warranty. Please help. NOW HMA says t claim for oil consumption and repairs were denied due to the vehicle being outside of warranty based on time and mileage. Once a claim is denied that is the final decision from HMA. This is untrue my vehicle is NOT out of warranty. Due to the oil consumption class action, and faulty engine put in ny car, the drivetran warranty was extended to 150K, and my vehicle is only has 115K and 7 years old. Hyundai put a bad engine in my vehicle to begin with. A few months ago I got a oil change at Firestone, 4 weeks later there wasn't a drop of oil in my car, that is a problem. Everytime I got a oil change, I had to extra oil after 3-4 week INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Mar 2025 | LANE DEPARTURE,BACK OVER PREVENTION | BSD system stopped working one day along with the Rear Cross Traffic Alert.The button which operates system does not come and system does not work. Warning lamp lit on instrument panel and said" check B SD system" meaning the whole system doesn't work. Took to my local shop and they couldn't repair as they stated the system is a proprietary system the had no software. service bulletin #19-BE-009H was issued in 5-19 by Hyundai for this issue with car. So there is a know problem | Crash: No Fire: No | Unknown |
| Mar 2025 | POWER TRAIN,ENGINE | I was going 80 mph on the interstate and suddenly my car went into limp mode and shooked really hard and dropped to 60 mph. I had to swerve to go onto the side of the road. The car behind me almost rammed into me. I contacted hampton hyundai for days to schedule an appt. I finally was able to drop off my vehicle to them but now they are telling me they have to do an oil consumption test but my car is in limp mode and it shakes when I drive it. The car is dangerous and they are trying to charge me $500 for a fuel pump replacement ( which I have a warranty of but they notified me that does not count but it matches exactly the possible reason). As you can see in the documents, they did not note that my fuel pump was broken. They just asked if I wanted to pay it so they can get started. I get normal oil changes done. They haven't even done a rod bearing test but just looked at the knock sensor and was telling me that they wanted to charge me to get that changed. | Crash: No Fire: No | Unknown |
| Feb 2025 | UNKNOWN OR OTHER | When I bought the car from Mathews in Marion Ohio the car looked like it was already in some form of accident due to a previous owner and I was unaware what caused the accident or any other problems with the vehicle upon buying. I was not presented with a carfax. I have electrical tape at the bottom of my bumper and there’s a problem with acceleration. It accelerates by itself and veers right when I take my hand off the wheel. I’m afraid to drive my car on the highway. I have complained about this problem to Mathews twice. I am now in a loaner until they figure out what’s going on. | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | Car does not when temperature drops below 30 degrees (Fahrenheit) even when garaged so you cannot drive car and u have to be towed several times at night. Local dealer stated unaware of issues but there is forum of Hyundai owners who have this problem with 2018 sonata. A local mechanic studied issue and did replacement on the relay switch and starter and now car starts in cold weather. It took me four years is stress and I put in complaint to Hyundai and they did nothing to compensate me for parts. This is a very big issue to be somewhere called late at night and not have reliable transportation. | Crash: No Fire: No | Unknown |
| Feb 2025 | ENGINE | Possible engine recall engine makes nose continuously stay low on oil.Bulletin came out about possible engine recall | Crash: No Fire: No | Unknown |
| Feb 2025 | UNKNOWN OR OTHER | I looked up my car on carfax and it shows a 3 different odometer readings. on 10/14/19 it had 15.125 miles. On 03/04/21 it had 61,284 miles. On 02/01/2022 it had 30,371 miles And finally on 3/3/23 it had 38,269 miles. This clearly shows that somewhere along the line, the odometer was changed. My car has been on the shop on several occasions in the less than 2 year time frame | Crash: No Fire: No | Unknown |
| Jan 2025 | SUSPENSION,ENGINE | The contact owns a 2018 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the vehicle lost motive power. The check engine warning light was illuminated. Additionally, engine oil was leaking onto the ground while the vehicle was parked. The contact stated that the dealer had previously replaced the spark plugs, and cylinders #3 and #4 twice, and an independent mechanic had replaced the front driver's side CV axle. The vehicle was towed back to the dealer, who determined that the engine had internal defects. The contact was informed that the engine and front CV axles needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but refused to replace the engine. The failure mileage was approximately 86,800. | Crash: No Fire: No Towed | 86,800 |