2018 Hyundai Sonata Engine

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.

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 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

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.

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.

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.

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 .

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.

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.

See attached document for complaint.

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

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.

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 am seeing online, this is a common problem with the engines in these cars. So many people are having their engines blow, and it also causes the catalytic converters to go out on these cars. We are not the 1st owners, and it is not u Der warranty, so hyundai won't do anything to help us. Even if they did, they are charging people around $1000 to clean the engine and then making people do oil consumption tests where they over fill the oil so that it doesn't run out in the time they make you drive it. This company is not standing behind there cars and they know these engines have problems! The car is available for inspection.

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 to do a diagnosis. The car was driven for 4 months and the knock sensor went off again. I took it to the dealer and they checked the bearing clearance and it passed the test. The oil was also low and the dealer recommended doing a combustion chamber clean. I spent $564 to get the combustion chamber cleaned. Less than three weeks later, the knock sensor went off again. I took it to the dealer and they measured the bearing clearances and they came back as "passed". I elevated the complaint to Hyundai and they responded that they will defer to the dealer technicians' recommendations and findings and did not offer to do anything to help. The dealer the drove the car to see if they could trigger the knock sensor which was unsuccessful. After expressing my disappointment and dissatisfaction, the dealer said there was nothing else they could do and the car was returned to me. I am concerned with the safety of this vehicle as entering Limp Mode on a highway represents a safety issue that Hyundai does not seem to be concerned about.

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.

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.

The contact owns a 2018 Hyundai Sonata. The contact stated engine oil constantly needed to be added between 1,200 and 1,800 miles. An independent mechanic was contacted. The vehicle was taken to an independent mechanic, and the contact was informed that there were no leaks found, and that the engine was in good operational order. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 118,000.

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 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.

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.

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?

Crack oil pan

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.

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