2018 Hyundai Sonata: engine knocking or ticking

Filed Jun 19, 2026 · Engine · NJ · fire

Vehicle caught fire after repeatedly taking it to Hyundai for service . I complained about the oil consumption and knocking noises while the vehicle was still under warranty and it was denied.

Filed May 12, 2026 · Engine, Fuel system · CA

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

Filed Mar 21, 2026 · Engine, Fuel system · AZ

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.

Filed Jan 6, 2026 · Engine · NC

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.

Filed Nov 22, 2025 · Engine, Fuel system · OH

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, hesitation during acceleration, and near-stalling. One incident was so loud and aggressive that it felt like the engine was going to come out of the hood. These symptoms pose a serious safety risk while driving. I brought the car to a Hyundai dealership at approximately 118,000 miles for an oil-consumption test. The vehicle failed that test, clearly confirming excessive oil consumption. Despite this, Hyundai refused to provide repair, internal engine cleaning, or engine replacement, claiming the vehicle was already over 100,000 miles I have maintained this vehicle responsibly and have documentation of regular oil changes, spark-plug replacements, inspections, and diagnostic reports. Despite my efforts, the issue continues to worsen, and the vehicle remains unsafe and unreliable. This ongoing problem has caused significant financial strain, emotional stress, lost time, and fear of engine failure while driving. Based on countless similar complaints from other Hyundai owners, this appear

Filed Oct 15, 2025 · Engine · PA

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.

Filed Oct 12, 2025 · Engine · IL

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 .

Filed Sep 8, 2025 · Engine · LA

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?

Filed Aug 18, 2025 · Electrical, Engine · OH

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.

Filed Aug 15, 2025 · Engine · OH

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.

Filed Aug 11, 2025 · Engine, Transmission · OH

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.

Filed Aug 6, 2025 · Engine, Fuel system · 72,000 miles · TX

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.