2018 HYUNDAI SONATA Engine Problems

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...

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.

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....

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

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...

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.

While driving on the highway, my 2018 Hyundai Sonata experienced sudden loss of engine power and became undrivable. The failure occurred without warning at approximately 86,500 miles. At the time of the incident, there were two children in the vehicle, and the breakdown occurred at night in cold temperatures (approximately 20°F). An authorized Hyundai dealership later diagnosed zero compression in cylinder 3 and confirmed a cracked piston, recommending full engine replacement. The sudden loss of power while driving created a safety risk due to traffic conditions and environmental exposure.

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.

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.

I am submitting a formal complaint regarding ongoing and severe engine issues with my 2018 Hyundai Sonata SE. Despite proper maintenance, the vehicle has developed extreme oil consumption and misfire problems that have made the car unreliable, unsafe, and financially burdensome. Beginning around 118,000 miles, the vehicle started consuming oil so rapidly that I was forced to completely replace the oil every 1–2 weeks because it would run dangerously low or nearly empty. This level of oil loss is not normal, acceptable, or sustainable. I have detailed documentation, receipts, mileage logs, and maintenance history supporting this. In addition to oil consumption, the vehicle has repeatedly misfired, produced diagnostic trouble codes, and fouled spark plugs with oil. I have been forced to replace spark plugs approximately every two weeks, which is clearly abnormal for any modern vehicle. On multiple occasions, the vehicle has experienced violent knocking noises, severe loss of power,...

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.

Unknown. 2018 Hyundai Sonata engine has failed. Only purchased the vehicle in December 2024, and the engine is defective. There is much information, via research, indicating that Hyundai is aware of the engine issues with this year vehicle, but are unwilling to make amends. Vehicle has 100,189 miles.

Engine consumes oil, more than 1 quart a week. started misfiring on a trip and dealer stated that engine needs to be replaced since valve was burnt. have 116k miles on car and have been diligent in maintenance.

I bought my daughter this car a little over a year ago to drive to college. A few weeks after we bought the car we noticed the engine oil was low. We began checking it and had to continuously add more oil between oil changes. Now we are having to put 1-1 1/2 quarts of oil in her car every week. It also smokes when it's first crank and when accelerating. I am worried it will break down on her while driving to or from school, or in the middle of an intersection where she could be run over or hurt. We now owe more money than it is supposed to be worth, and we are stuck. When the oil gets low there are no warning lights or anything that comes on to let us know it's low. We have to keep a constant check on it. From what I...

In December 2024, my 2018 Hyundai Sonata went into limp mode after the knock sensor was triggered. This happened when my son was driving home from school. I took it to my local mechanic and he said the car was low on oil. We put more oil in it and reset the sensor. In March, the knock sensor was triggered and it again went into limp mode while my son was driving back to school. We took it into a shop and it was again low on oil. Oil was added and then the sensor was reset. The sensor went off again later in March and our mechanic told us to take it to Hyundai and have it checked for the rod bearing issue common with this model and year of Hyundai. He cleared the error and when I contacted the dealer, they said they needed the warning lights on...

While driving my vehicle one day, the engine blew out. This was caused by a malfunction from connecting rod bearing wear. I could have easily been rear ended. Hyundai was aware of the issue, but it was never resolved for me at least. They stated this in a letter addressed to me. There no warning lamps .

It has oil consumption issues

Oil consumption was ridiculously high, changing oil/topping off oil constantly. Car would not accelerate over 30 mph without sputtering and rumbling. I had mechanic diagnose bad sparks plugs due to sitting in oil from leaking. After I had them repaired/replaced the car drove great for 1 day, then decided to die in the middle of a busy intersection while I had my teenage son in the car with me. My son and I had to PUSH it out of the busy intersection onto a side street to get out of the way! I had it towed to Hyundai dealer who said the spark plugs were bad and that the fuel pressure sensor and gdi pump were faulty and needed replacement. Left front lower control arm/ball joint assembly also requires fix. To the tune of $3000 + . It’s been at dealer for past few months until I can afford the...

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...

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...

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.

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.

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...

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...

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....

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.

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.

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...

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

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.

Check engine light keeps coming on got it looked at , certain parts replaced & it’s still on something to do with the air filter

Engine burns oil about every 200, need to top off oil. Dealership and Hyundai corporate office will not take responsibility.

Car keeps burning oil faster than normal which has resulted in car not starting multiple times even after a month old oil change.

Crack oil pan

My 2018 Hyundai Sonata caught fire unexpectedly while parked. The engine suddenly began smoking, then the vehicle ignited and was severely damaged. I am still financing the vehicle through Capital One. After researching, I discovered that my vehicle’s engine is part of a known Hyundai recall due to fire risk (Theta II engine defect). I had no prior warning or engine-related issues that would have predicted this. I strongly believe the fire was caused by a manufacturing defect, and I’m requesting that NHTSA investigate Hyundai’s handling of this issue and ensure victims like myself are compensated — even if not physically injured. I can provide photos, a fire report, and additional documentation if needed. Please let me know the next steps or if I qualify for any related recall recovery programs.

The engine shuts off, doesn’t start, check engine light flashing, losses power, jerks while driving it, i will get it up yo speed then will shut off or won’t move.

⸻ In early 2024, I brought my vehicle to a Hyundai dealership due to rapid oil loss. I reported having to refill the oil weekly and suspected a leak. They diagnosed a cracked oil pan, claimed to fix it, and returned the car. However, immediately after, the car continued burning oil at an alarming rate. I was forced to buy and add oil every single week, spending hundreds of dollars to maintain drivability. Shortly after the repair, I began experiencing erratic dashboard warnings. The check engine light would frequently come on and off. The oil lamp illuminated every few days. These symptoms were persistent, not isolated incidents. Despite reporting the issue again, I was told the oil burning was “normal” for Hyundai engines and nothing to worry about. That response put my safety and my child’s safety at risk, as I was unknowingly driving a vehicle with worsening engine damage....

I purchased this vehicle from the seller the vehicle then immediately gave me engine issues. I contacted the Hyundai dealership which the vehicle got recent services with. They told me that the claim was denied even though the car has an extended warranty until 120,000 miles and the vehicle has less than that due to a regular oil changes they recommended me call Hyundai corporate to see if they can help out. I then contacted Hyundai corporate, and they essentially stated the same thing saying that the vehicle did not qualify for the extended warranty due to outside factors which were the irregular oil changes. I let them know that the vehicle did not get regular oil changes and I provided them with a Carfax report they then told me that in order for the card to be classified as getting regular oil changes and maintenance is every 5000 miles...

The car in recent months has twice lost power and been rendered in operable on the side of the road until it could be limped home. I had the car serviced last year for a recall of a fuel filter gasket and at that time I was informed that I also had an update done for a (k knock?) sensor prior done on the car before purchase. I inquired about what that was, and they told me at the time it was for an engine recall because that particular engine I have is known to have rod bearing failure and consume oil without any trace of where it goes and piston rattle. I told the gentleman after my fuel gasket was taken care of that I would like to look into that because I have the symptoms and would like to know. At that point in time, I was told...

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.

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,...

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.

CAR STALLS; ENGINE IMPAIRED; OIL CONSUMPTION PROBLEM

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.

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.

I have to put a quart of oil in every week. It burns oil.

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.

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.

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.

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.