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 |
|---|---|---|---|---|
| May 2026 | POWER TRAIN,ENGINE | 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. | Crash: No Fire: No | Unknown |
| May 2026 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | 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 | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE,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. | Crash: No Fire: No | Unknown |
| May 2026 | ENGINE | 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. | Crash: No Fire: No | Unknown |
| Apr 2026 | STRUCTURE | 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. | Crash: No Fire: No | Unknown |
| Apr 2026 | FUEL/PROPULSION SYSTEM | Throttle response intermittent problem no acceleration since new. No codes available. When entering traffic engine stall factor flat spot. Been to dealer many times (Bud Clary) and just recently (04/26) confirmed the fuel pump is the problem. Unable to confirm because of no "codes". Will not replace or register for recall without proper codes. No check engine lamp. No inspection by police or insurance only the dealership service department is aware of the problem. | Crash: No Fire: No | Unknown |
| Apr 2026 | ELECTRICAL SYSTEM,UNKNOWN OR OTHER,SERVICE BRAKES | We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds or long braking. The only thing that made it stop was to unplug the abs but then other parts of the car stopped working like the speedometer and the sensors around the car. So we got the abs replaced but the new one started doing the same thing. We did some research and it sounds like the same issue Hyundai is having with the palisade. The incident that made us get it replaced to begin with was were driving down the road and we got to a traffic light but when we tried to brake they just didn’t work so we drove through the red light luckily the one person who was supposed to be going saw us and didn’t pull out in front of us so we didn’t get hit. We haven’t taken it to the dealership yet but my sister who teaches automotive repair at the community college is the one who diagnosed it so she said we should report it here so maybe it won’t happen to anyone else. Before we had the brake issue we were having problems with basically everything on the dash not working randomly. We’d be driving down the road and the speedometer and the outside sensors and the gas gauge and the traction control all would go out at the same time it’s the same stuff that went out when we had the abs unplugged so it seems that might be related. | Crash: No Fire: No | Unknown |
| Apr 2026 | ENGINE,FUEL/PROPULSION SYSTEM | Had an oil change, then 2 weeks later car making noise, checked the oil and it was completely empty, so we refilled the oil. Then a month after again same issue no oil, refilled it again and now a week later it's 2 quarts low already. Also when I come to a complete stop when it is time to go again it's very slow at going or if I try to excel it takes it a very long time to actually excel I think something's wrong with the fuel pump | Crash: No Fire: No | Unknown |
| Mar 2026 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | I bought a 2018 Hyundai Sonata a few years back. No warranty. Used. 110,000 miles. A few short months after I purchased it, it stopped working. I took it back to the same dealership where I purchased it and they said they had to replace the coil packs and spark plugs and clean something in the engine out because there's a defect in the engine. I paid $500. Fast forward a few months later. Same thing happens. I take it to an auto repair shop because it's cheaper and the mechanic says he deals with these same issues with other customers who have similar year, make, and models. This pattern continues to this very day. It broke down while I was working my 2nd job. I have a daughter. She plays sports. I have a second job. I need this problem completely alleviated as quickly as possible. Like a lot of the American public, I don't have extra money to keep up with anything beyond the normal maintenance of my vehicle. I keep it up to date with all oil changes. What can you do to get me a vehicle I can trust and it not break down every couple months and cost $300-$600 each time? I don't have good credit (I'm working on that) I have medical issues that I have to visit my doctor for every 3 months. I have the loan through Capital One and they don't offer refinancing. My father who has passed was a car salesman his entire career. I just need reliable transportation and if it's a motor problem like they say then I shouldn't be liable to fix it. The manufacturer should. Please let me know if you need any service records from me. Oh and I also have to put about $20 worth of oil in it every week or so between oil changes. My local oil change guys unfortunately know me very well. | Crash: No Fire: No | Unknown |
| Mar 2026 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | The vehicle developed a progressive engine failure beginning in early 2024, including loud knocking noises at cold start and visible white/gray/black exhaust smoke. The condition worsened over time. In February 2026, the failure escalated to active oil discharge from the exhaust pipe while the engine was running. Oil exiting through the exhaust indicates internal engine failure (such as piston rings, cylinder walls, or valve seal failure), not an external leak. This creates a safety risk including potential loss of power while driving, risk of engine seizure, and possible fire hazard due to oil in the exhaust system. The condition has been documented on video multiple times and was shown to dealership personnel. The vehicle was taken to a Hyundai dealership for evaluation and remains available for inspection. Despite this, no written diagnostic findings or repair determination have been provided. The issue has been persistent, progressive, and reproducible, and represents a potential defect affecting engine integrity and safe operation of the vehicle. | Crash: No Fire: No | Unknown |
| Mar 2026 | POWER TRAIN,ELECTRICAL SYSTEM,ENGINE | The vehicle had safety and mechanical problems shortly after purchase, even with low mileage. The issues included warning lights, abnormal noises, repeated mechanical failures, and poor performance that affected the safe operation of the vehicle. These problems started early and continued over time despite repairs and maintenance. Before the incident, the vehicle showed signs of malfunction, including instability while driving and loss of normal performance. These symptoms created an unsafe driving condition and increased the risk of a crash. I believe the vehicle had defects from the beginning that affected safety. The failure contributed to the accident that occurred while driving on the highway, putting my life and my family at risk. | Crash: Yes Fire: No | Unknown |
| Mar 2026 | ENGINE | 2018 Hyundai Sonata 2.4L Theta II engine experiencing severe oil consumption and loss of oil pressure. Oil pressure warning light actively blinking and dipstick completely dry. This is consistent with the known Theta II engine defect subject to prior NHTSA investigations and class action settlements. Mission Hills Hyundai documented low oil concern in service notes during December 2025 visit but failed to take any action and returned the vehicle without repair. Hyundai Consumer Affairs has been unresponsive and provided conflicting information regarding recall completion on this vehicle. This is a serious safety defect that puts the driver at risk of engine failure while operating the vehicle. | Crash: No Fire: No | Unknown |
| Mar 2026 | ENGINE | Excessive Oil Burning and Oil Consumption. Oil turns black abnormally quickly (within the first 500-1000 miles) even though recommended Full-Synthetic Oil is used. Engine has intermittent rough idle once engine is warm. Occasionally engine experiences "near-stall" and "misfire event", causing the battery light to flash on dashboard. >>>Oil consumption rate is approximately 3-4 quarts per 1,000 miles<<< ***Maintenance completed since purchase*** Coolant Flush - Replaced PCV Valve (NEW) - Replaced Valve cover Gasket + Oil Pan / Oil Pan Gasket (recommended by dealer) (NEW) - Replaced Spark Plugs (recommended by dealer) (NEW) - Replaced Battery (NEW) - Replaced Alternator (NEW) - Replaced both engine accessory belts (NEW) - Replaced 150A main fuse (located on positive battery terminal) (NEW) - Used Hyundai brand oil filters - Used Chevron/Techron Complete Fuel system cleaner twice, between and at oil change (as recommended by "Twin City Hyundai" dealer in Alcoa, TN) ***Had dealership inspect it for approval of known Federal Recall on GDI Engines for excessive oil consumption / engine seizing issues; dealership claimed it did not pass re-call approval*** SYMPTOMS STILL PERSIST Mileage is now approx. 80K | Crash: No Fire: No | Unknown |
| Feb 2026 | ENGINE | The component involved is the engine (2.4L Theta II gasoline engine) in my 2018 Hyundai Sonata. The malfunction involves excessive internal engine oil consumption between oil changes. The vehicle consumes oil at an abnormal rate, requiring frequent top-offs to prevent low oil levels. The vehicle is available for inspection upon request. This condition creates a safety risk because excessive oil consumption can lead to critically low oil levels, engine seizure, sudden engine stall, or loss of propulsion while driving. A sudden engine stall or loss of power while operating at highway speeds could increase the risk of a crash. The problem has been inspected and documented by an authorized Hyundai dealership. During service, the dealership recorded that the customer reported oil burning between oil changes and noted evidence of engine oil consumption. No permanent repair has been performed. The issue remains unresolved. Hyundai Motor America has not physically inspected the vehicle directly but has reviewed the case through customer care. The manufacturer has required additional diagnostic testing at the owner’s expense as a condition of further evaluation and declined to authorize testing at no cost or provide assurance of reimbursement. No crash, fire, or injury has occurred to date. The vehicle has not been inspected by police or insurance representatives. There were no warning lamps illuminated at the time the oil consumption was first observed. The condition was first noticed when oil levels were found to be significantly low between scheduled oil changes. The issue has been ongoing and progressive. Given the known history of engine-related issues involving Hyundai Theta II engines, I am submitting this complaint due to concerns that continued oil consumption may result in engine failure, sudden stall, or loss of propulsion while driving, creating a potential safety hazard. The vehicle remains in service but the condition has not been corrected. | Crash: No Fire: No | Unknown |
| Feb 2026 | ENGINE | The oil pan is starting to crack, a small drip is now happening but dealership says it could spilt and cause the engine to seize while driving. The pan looks very flimsy compared to my Ford and Toyota. | Crash: No Fire: No | Unknown |
| Feb 2026 | ELECTRICAL SYSTEM,ENGINE | To Whom It May Concern, My name is [XXX] , and I am formally escalating serious ongoing issues with my 2018 Hyundai Sonata. Despite repeated attempts to resolve these concerns through the dealership, my vehicle continues to experience excessive oil consumption, engine failures, and additional mechanical issues, all while under warranty. I am now seeking immediate corporate intervention. Timeline of Events and Mismanagement: •2024(~62000 miles): First reported oil leak and excessive oil consumption. Directed to complete multiple 1,000-mile oil consumption tests. I complied fully. •2024: Repeatedly redirected between service advisors, received conflicting instructions, misleading guidance, and poor communication. No effective resolution was provided. •2025: Completed extensive additional diagnostic testing as requested. Despite full compliance, no clear corrective action was taken. •2024–Present: Vehicle brought to Hyundai on US 19 in New Port Richey approximately 13–15 times for engine-related concerns. Each visit demonstrated neglect, miscommunication, and failure to properly address documented issues. •February 11, 2026: After proper diagnostics, vehicle found to have two additional oil leaks, including a head gasket and valve cover requiring replacement, with total estimated repair costs exceeding $3,000. I was advised I must repeat all testing already completed in 2024 before final determination. •Vehicle is currently at 71,332 miles. Impact: •Delays and repeated unnecessary testing pushed my vehicle beyond warranty limits. •Mismanagement caused significant financial burden, emotional stress, and frustration. •If initial oil consumption issues had been properly addressed under warranty, the current extensive engine failures could likely have been avoided. Immediate Requests: 1Full review of my complete service and diagnostic history. 2Warranty or goodwill coverage for all necessary engine repairs, including head gasket and valve cover INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Feb 2026 | ENGINE | While driving the vehicle, I repeatedly must check and put oil in. (On average once per week) I took the car to an auto shop where I was told that the engine was bad and I must get a new one. I kept driving, putting oil in as needed, then the car in the middle of driving started to shudder and the check engine light came on. I parked the car and haven't driven it since | Crash: No Fire: No | Unknown |
| Jan 2026 | POWER TRAIN,ELECTRICAL SYSTEM,ENGINE | Unknown what system failed. The vehicle is at an impound lot and can be inspected on request. Police and fire department were on the scene. Police did provide a report # , and fire department provided a fire rescue case number. Safety of driver was put at risk due to the fire and potential for burning or even death. Other drivers could have been at risk if traffic had not allowed for quick movement to side of the road. No warning lamps had been on prior to the drive and none prior to fire. First indication was a burning smell while driving. As pulling over, another driver honked to alert to fire he could see from rear of ca,. before I noticed the flames. Upon getting out of car first flames I saw appeared to be coming from under passenger side of car. The fire department arrived about 15 minutes after pulling to side of the road. The car was fully engulfed in flames. They then extinguished the fire. Police saw vehicle and insurance will examine. Apparently this is a known issue in Hyundai of which this vehicle had no open recalls pertaining to such. | Crash: No Fire: Yes | Unknown |
| Jan 2026 | AIR BAGS | The three airbags in the car (on the driver's weel, driver's knee, and the passenger's side) deployed while driving on a normal street at a speed of 50 miles/hour. This is an unexpected behavior of a car at a normal speed. I need help to fix this car and know what is the reason this happened. | Crash: No Fire: No | Unknown |
| Jan 2026 | ENGINE AND ENGINE COOLING | The contact owns a 2018 Hyundai Sonata. The contact stated that while driving approximately 60 MPH, the vehicle started to vibrate roughly. The contact felt the vibration in the steering wheel. The check engine warning light was illuminated. The contact slowed down and pulled off the roadway. The contact turned off and restarted the vehicle and was able to shift to drive(D); however, the vehicle was hesitating and failed to accelerate as needed. The contact drove the vehicle to an independent mechanic at speeds no greater than 40 MPH. The mechanic scanned the vehicle and retrieved codes for a misfire in the engine. The mechanic advised the contact to take the vehicle to a dealer for assistance. The vehicle was towed to the local dealer. The vehicle was not yet diagnosed or repaired. The manufacturer was informed of the failure. The contact requested an engine replacement that was denied by the manufacturer. The failure mileage was approximately 138,000. | Crash: No Fire: No Towed | 138,000 |
| Jan 2026 | ENGINE | Engine oil consumption issues. My 2018 Hyundai Elantra falls within the dates of this issue. I had an oil consumption issue done and the dealership claimed it passed. I have to put oil in my car every 3 weeks and change spark plugs at the same time because of engine leaking oil in to them. My engine light is always on, knocking and pinging sound, poor performance issues, and blue smoke coming out of tail pipe. I have stuck on the side of the highway several times and have misses work because of the ongoing issues with the engine. How can a oil consumption issue pass and i have all these issues. I have spent several hundreds of dollars on oil, spark plugs, frequent oil changes and tows. There was only 85,000 miles when I started to notice the problem and had only owned it for 6 months. | Crash: No Fire: No | Unknown |
| Dec 2025 | ELECTRICAL SYSTEM,UNKNOWN OR OTHER | Intermittent no-crank, no-start condition. Dash lights illuminate, push-button start produces no response. Brake pedal applied. Vehicle becomes immobilized without warning. I’ve been stranded on multiple occasions. Unable to commute to work, or home. Most recently on December 19,2025 the car completely shut off while driving on the highway. | Crash: No Fire: No | Unknown |
| Dec 2025 | ENGINE AND ENGINE COOLING | The contact owns a 2018 Hyundai Sonata. The contact stated that while receiving an oil change, the technician advised that the oil level was very low. The contact stated that the low oil warning was intermittently illuminated. The contact was advised to take the vehicle to a dealer to be diagnosed. The contact had taken the vehicle to a local dealer, where an oil consumption test was performed. The contact was advised that the vehicle was operating normally. The contact stated that the low oil warning light was illuminated again. The vehicle was taken back to the same dealer, and the oil level was topped off; another oil consumption test was suggested. The contact researched online and related the failure to a known issue of oil consumption that could lead to engine failure. The contact called the manufacturer and asked about an engine replacement because the vehicle was still under warranty. The manufacturer informed the contact that a combustion cleaning had to be performed to determine if the engine needed to be replaced. The contact stated that the vehicle was taken back to the same dealer who performed the combustion cleaning; however, the excessive oil consumption remained, and there was evidence of burned oil coming from the exhaust pipe. The contact called the dealer and was advised that another oil consumption test and combustion cleaning were needed. The vehicle was not repaired. The failure mileage was 103,235. | Crash: No Fire: No | 103,235 |
| Dec 2025 | UNKNOWN OR OTHER | Excessive oil consumption. I am routinely getting notifications of low oil about 1,000 miles before the oil change is due. When I bring it in for an oil change it is nearly empty. No signs of leaks anywhere. | Crash: No Fire: No | Unknown |
| Dec 2025 | AIR BAGS | I am Detective [XXX] #XXX with Austin Police Department Vehicular Homicide Unit and I worked a fatal crash [XXX]. The damage to the vehicle two vehicle should not have caused a death. The airbag became detached from the steering wheel and impaled into the drivers chest. I do have pictures but they are crime scene pictures and pictures of the decedent so I am not attaching them but if someone contacts me I can arrange that. I do not know the speed but I am going to image the module next week. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: Yes Fire: No Fatalities: 1 | Unknown |