2016 Hyundai Sonata Fuel system Problems

My 2016 Hyundai Sonata (VIN: [XXX]) has a serious safety issue involving excessive engine oil consumption. The vehicle loses oil rapidly between changes and requires frequent top‑offs to avoid engine damage. This creates a risk of sudden engine failure while driving. The dealership, South Charlotte Hyundai (10518 Cadillac Street, Pineville, NC 28134), refused to perform Hyundai’s official oil‑consumption test. Instead, they told me to pay $750 for a combustion cleaning and stated it would not fix the underlying problem. They would not document the refusal or provide any testing. I contacted Hyundai Corporate multiple times: • May 21, 2026 – Executive Office complaint submitted • June 3, 2026 – Follow‑up sent • June 29, 2026 – Regional escalation sent My Hyundai case number is XXX. As of XXX Hyundai has not responded to any of my Executive Office or Regional escalations. Only Customer Care replied with a template denial and no investigation. I have been waiting over two months with no action from Hyundai Corporate. I am reporting this because the manufacturer has not addressed a safety‑related defect, the dealership refused required testing, and the vehicle continues to consume oil abnormally. I am requesting NHTSA’s assistance in documenting this defect and Hyundai’s lack of response. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11755304

Incident

Feb 27, 2026

I have a car covered by the Theta II Settlement. Engine, fuel system. Metal shavings found in oil and oil is diluted with fuel and oil if overfilled 1 inch above full mark on dipstick upon pickup from dealership. The vehicle is available for inspection at my residence; however, it is currently grounded as a known safety hazard. The vehicle is exhibiting symptoms of imminent engine failure (audible knocking, P0011 code, and oil dilution). Despite being shown evidence of this(photo and video of oil overfill and watery viscosity) , the manufacturer instructed me to continue operating the vehicle, placing myself, and other drivers at risk of a high-speed collision or vehicle fire. The symptoms (P0011 code and engine noise) were confirmed by an independent mechanic on March 25th 2026. However, during the official Bearing Clearance Test (BCT), the dealership intentionally overfilled the engine oil by 3 quarts (documented via photograph) to muffle mechanical noise and artificially pass the diagnostic and issued a pass on all inspections despite the oil hazard. Hyundai Corporate Case Manager Nikulmar Dhabi has admitted on record that the dealer was out of compliance by "being outside the standard notification time" yet they refuse to provide a safety-compliant remedy. Warning Symptoms & Appearance: Symptoms first appeared months ago when I repeatedly got a P0011 code, however On march 24th 2026 I received an engine light with a P0011 and the car going into limp mode while i drove. Warning signs included a persistent Check Engine Light (P0011) and audible metallic knocking. Upon checking the oil myself after the dealer "inspected" it, I discovered the oil was 3 quarts over the "Full" line, which is a deceptive practice used to mask rod bearing failure.

NHTSA ID

11731963

Incident

Mar 25, 2026

I am writing about my concerns on a 2016 Hyundai Sonata SE that I purchased for my daughter in October 2023. After purchasing I took it to my local Hyundai dealer to have it checked out. It was one of the cars that came with a lifetime warranty for the rods DO TO A DEFECT.On January 2024 my daughter was driving on the freeway when all of a sudden it just stopped accelerating and when checked it was a Knock sensor detection system. The dealer took it in and inspected and said it was a defective sensor and replaced it.This made me uncomfortable as I felt the sensor did its job and it was just a matter of time before the rod blew through.During the next few months it became very apparent that the car was going through unbelievable amounts of oil.It had a ticking so we replaced all the spark plugs and noticed oil saturating the plugs and realized a leak in the valve cover gasket which was also replaced.We thought this might be the cause but no oil was on the ground and nowhere on the engine.I just thought it was burning oil but no indicator lights were going off. The car could have no oil and it would not let us know. She's lucky to drive 300 miles a month.She has complained of a strong gas oder and we replaced 2 gas caps and went back to the Hyundai dealer.They told us there's a problem with the fuel filter and pump.If we pay $273 of inspections it might cover it if it's a failing part, and when I did the oil change the car was very low on oil despite the fact that we check it monthly and put 3 quarts of oil in the car.Her car is consuming 3-4 quarts of oil per every 250 miles.This could cause her engine to fail and possibly throw a rod which given the fact she has already taken out one Knock sensor it is just waiting to happen.So as oil disappears every few hundred miles without a warning the engine locks up and if a rod punches through onto the exhaust this can cause it to stall and potentially catch on fire especially when it wreaks of gas from the fuel filter.

NHTSA ID

11731891

Incident

Jan 2, 2024

This complaint is NOT related to the existing recall associated with this vehicle. The vehicle is experiencing a serious loss of power and acceleration issue. The car is unable to accelerate past approximately 60 mph. When pressing the accelerator fully, the vehicle does not respond or increase speed. While attempting to accelerate, the engine RPM increases and then suddenly drops repeatedly, causing the vehicle to struggle to maintain speed. This behavior is consistent and occurs during normal driving conditions. This creates a dangerous situation, especially when merging onto highways or attempting to accelerate in traffic, as the vehicle cannot respond when needed. The issue has occurred multiple times and makes the vehicle unsafe and unreliable to operate.

NHTSA ID

11724931

Incident

Mar 9, 2026

My 2016 Hyundai Sonata (2.0T/2.4L engine) has been experiencing loss of motive power and severe engine stumbling at stoplights, creating an unreasonable risk of a crash in traffic. The Check Engine light is on with DTC P0010. Upon inspection, the internal oil seal plug at the intake camshaft E-CVVT has become unseated, causing an active oil leak. This matches the exact defect and symptoms (elevated idle of 1,200–1,400 RPM and power reduction) described in Hyundai Service Campaign TX3 (TSB 15-01-022-1). While that campaign only applied to 2015 models, my 2016 vehicle has suffered the identical failure. I am requesting that this safety-related defect be investigated for 2016 models to prevent potential engine fires from oil leaks or accidents from sudden power loss

NHTSA ID

11714812

Incident

Jan 29, 2026

This vehicle has experienced multiple hybrid system failures while driving, including a complete loss of power “Hybrid System Warning – Turn Engine Off” on the interstate in June 2022 through November 2025. These events have placed me and my loved ones in dangerous driving situations. Despite a warranty‑covered engine replacement at 82,015 miles (January 2023), the same hybrid system issues have recurred. Hyundai initially indicated a warranty claim was submitted, then told me there was no record of any claim in the system. The dealership claims it was denied — creating a serious inconsistency in communication and accountability. In addition, I have identified multiple NHTSA complaints in the database from other owners of 2016 Sonata Hybrids (VINs beginning with KMHE) describing similar highway shutdowns and hybrid system failures, which raise concern about a broader, unaddressed safety defect not currently covered by existing TSB or recall actions. I am respectfully requesting: A regional inspection and review of my vehicle prior to any further work. A review of Hyundai’s handling of this warranty claim and the discrepancy between dealer and corporate communication. Assessment of whether the hybrid system failures in KMHE‑prefix Sonata Hybrids warrant further safety action.

NHTSA ID

11711987

Incident

Nov 5, 2025

The problem with my vehicle is a failure of internal engine components, specifically a known defect in the piston rings of the Hyundai Theta II engine. This failure causes excessive oil consumption, which is burned internally. The internal engine components have failed, leading to a widely documented defect in the Hyundai Theta II engine. The primary symptom, which began to get serious around 80,000 miles, is the constant need to add oil to the engine every two weeks. If I do not do this, the low oil warning light illuminates on the dashboard, serving as a continuous alert of the problem. This failure was officially confirmed by an authorized Hyundai dealership. About two weeks ago, they first documented that there were no external leaks on the vehicle. When I returned because the oil had been consumed again, they performed a new diagnostic, for which I paid over $300, that confirmed the engine is burning oil internally. The dealership, acting as the manufacturer's representative, is the only entity that has formally inspected the vehicle. The situation places my safety and the safety of others at serious risk. First, the oil consumption can lead to a sudden and catastrophic engine failure, resulting in a loss of power and control of the vehicle while in transit. More alarmingly, the guidance I received from Hyundai staff was to simply "wait for the engine to stop working or start making a lot of noise." As someone who depends on the car for a daily commute, following this dangerous recommendation is an unacceptable risk.

NHTSA ID

11692555

Incident

Oct 9, 2025

I am reporting a serious safety concern involving my 2016 Hyundai Sonata Hybrid, which has experienced multiple hybrid system shutdowns while driving. This includes repeated complete power loss incident on I-90 beginning in June 2022, when my daughter was driving home after her hospital shift. The vehicle displayed a “Hybrid System Warning – Turn Off Engine” message and had to be pushed off the highway and towed. This was the first of several hybrid-related failures that culminated in a full engine replacement under warranty at 82,015 miles — and now, the same hybrid system warning has returned at 127,592 miles, well within Hyundai’s 150,000-mile hybrid warranty. Hyundai is currently denying coverage. I am requesting that NHTSA investigate repeated hybrid system faults and warranty denial patterns in Korean-manufactured Sonata Hybrids.

NHTSA ID

11665618

Incident

Jun 24, 2022

I had engine issues back in 2021. I had to pay $600 for a part to be installed to fix the problem . The engine failed, the idle was violently lurching forward and would randomly Shut down. Recently the car shut down without warning again. Its scary.

NHTSA ID

11662102

Incident

May 19, 2025

Car keep stalling misfire just started muffler sound smoke lack of power when driving

NHTSA ID

11653089

Incident

Nov 7, 2024

The fuel pump where the fuel line connects to it is cracked and squirting fuel all over that area. Some time ago I started smelling fuel when getting close to the vehicle or when opening windows. Took it to a shop to have it checked out and the technician couldn’t find the problem, since there is no check engine light on or any type of warning. A few days ago I decided to check the bottom part of the fuel tank and noticed that there were traces of leaking fluid. Reached to it and checked it closely and certainly was fuel dripping. Checked the top of the tank where the fuel pump is and found out that the problem was there. Did some research online and found out that that’s a very common fail. I Would like to have it investigated and recall all those failing cars for my safety, my family’s safety and everyone else that trusted this company and is letting us down. First time I noticed this was back in 2022 and is when I took it to the shop.

NHTSA ID

11651130

Incident

Nov 16, 2024

I was driving a 2016 Hyundai Sonata on a mountain highway and it started to run rough and lose power dramatically when accelerating. A dangerous situation on a steep curvy highway that has many one lane sections. Shortly thereafter a dash light came on. There was no warnings or dash lights or symptoms prior to this incident. I took the vehicle to a mechanic and ran the code. It said there was a misfire in cylinder 3. Replaced the ignition coil and spark plug for cylinder 3 and it did not fix the problem. The mechanic then pulled the motor to check the valves. Valve 3 was burnt, had a hole and stuck open. The car had approximately 75,180 miles. Well within the warranty time frame of 10yrs or 100,000 miles for an original purchaser. The mechanic had the valve machined, and replaced the head gasket and reassembled the the motor. I picked the car up and drove it home. Within 3 days I noticed an oil leak under neath the car where the engine bay is. I took the car back to the mechanic and he diagnosed a hairline crack in the oil pan. After some research I came across a letter from NHTSA on a defect investigation of Hyundai/Kia oil drain pan assemblies. This is exactly what happened to my car! I have paid 3500.00 to fix a car that has less than 76,000 miles. Hyundai needs to do better.

NHTSA ID

11642598

Incident

Dec 13, 2024

My 2016 Hyundai Sonata started using and leaking oil in August 2023 when it had about 129,000 miles and when you tried to go faster than 55 miles per hr. it would not accelerate. We feel there is a danger to drive it in traffic. We took it to the dealership in Pensacola, FL. They found a valve cover gasket had multiple leaks which they replaced. Found a code P1326 (whatever that means), Performed T3G campaign and followed a flow chart and BCT test passed. Don't know that any of this addressed the fact that the motor won't accelerate. Charged me $3,000 for something. Car ran okay for a while and started doing the same thing again. In June of 2024, took it to local mechanic who ran diagnostics and replaced a coil and plugs which cost another $600. It ran a little better until August 2024 and took it back to local mechanic who did another diagnostic and replaced 4 plugs and PCV valve for another $300. It's now November 2024 and the car won't accelerate over 55 mph and we can't use it to drive to work.

NHTSA ID

11622352

Incident

Aug 23, 2023

We were told from Tulsa Hyundai that our car was involved in a massive recall due to engine failure and that the warranty had been extended to 150,000 miles on Theta engines. They told us we had to follow the process in order to have a claim submitted to Hyundai corporate. They required us to pay for a valve gasket replacement and a valve cover gasket ($1000), then to take the car home and drive for 1000 miles and then bring it back in. We brought it back in and were required to pay for a combustion cleaning (around $800) and then take it home and drive it for 1000 miles. We brought it back in and they performed the oil consumption test. They then submitted the claim to Hyundai and we heard back the next day (9/18/2024) that they were denying they claim due to it being an issue with piston rings instead of rod bearing failure. I called Hyundai and they basically said there was nothing else they would do. They told us we could be reimbursed for the $1800 we had to spend to go through that process. Those fees were incurred were not necessary, especially when Hyundai is not going to replace the engine. Hyundai markets on their dealer websites, "engines for life", yet they will do nothing to replace our engine that is in failure.

NHTSA ID

11615223

Incident

Jul 10, 2024

Background Info : On November 28th, 2023 I filed a case with Hyundai Consumer Affairs due to smoke and sparks coming from my 2016 HYUNDAI SONATA engine. I was assigned to a Case Coordinator Carla who did not provide her last name at telephone 714-694-4963. She was my contact person for the repair. I signed a tow authorization on November 28th , 2023 authorizing HMA to tow the vehicle to the nearest Hyundai dealership due to some delays in coordination on behalf on my contact Carla and the dealership Pohanka Hyundai received my vehicle on approximately December 4th, 2023. Per correspondence from Carla she had contacted the dealership with no response until the 18th of December 2023; approximately two weeks after the dealership received my vehicle. She informed me that she had made countless attempts to reach a service team member for follow up on an inspection. On December 18th 2023 I got in contact with Joseph to inquire as to what his inspection found. He stated “That he did not see an oil leak and the car hand no oil.” I explained to him that was my car had been recently serviced at Jiffy Lube on August 1st 2023 at 44,664 miles for an oil change. Per Hyundai the oil should be changed every 3,000 to 5000 miles which I had not exceeded as my car had 46863 miles at the initial time of the service inspection that he performed. He then said “Jiffy lube did not put any oil in the car then” which was impossible. I made contact with the Jiffy Lube location who performed the oil change to get the record of my last oil change as Joseph had a differing opinion. I was informed that in fact the oil was changed and they could provide video proof if necessary. I then communicated this information to Joseph as well as provided a copy of the last oil change. I then was told that I needed a CVVT replacement, transmission flush and oil change. I attempted to address his initial diagnose of “no oil in the car” as I had proof that it had been changed and that they should do furthe

NHTSA ID

11569022

Incident

Jan 31, 2024

Car stalled check engine light came on took to auto zone said a engine problem

NHTSA ID

11545744

Incident

Sep 17, 2023

I keep having the same issue with this vehicle's fuel/propulsion system, power train, engine, cruise control. This vehicle is need it's fuel system cleaned now for a 3rd time in less then 2 years. I have done the high mileage maintenance on it as well. I drive the vehicle less than 5,000 miles a year. When I am driving the vehicle, it struggles to speed up, making me press on the gas repeatedly to get to the indicated speed limit. The vehicle does not slow down as it should when pressing on the brakes. I have to press repeatedly over and over and harder on the brakes in order for it to slow down. The vehicle jerks, speeds up without me pressing on the gas and sometimes it will not stop when prompted. I cannot put this vehicle on cruise control, because it speeds up and out of no where, it accelerates causing me to almost collide with another vehicle or object. Even when the vehicle is not in cruise control, the sudden jerks and acceleration puts me, my children and others in harm when it suddenly speeds up, jerks or will not stop in time. It makes a loud noise and jerks even when the car is in a resting position. It loses power, it speeds up when i need it to stay the same speed or slow down. I fear this vehicle is unsafe. I have reported these issues and a few more to the dealership who never responded, so I had to go over their heads, then finally I got a response from their Consumer Affairs' Department, as well as the BBB and they state because of the vehicle's age and/or mileage there is nothing they can do about it. Please help me. This is the only vehicle I have, and I am a single parent who cannot afford another vehicle. What is going on with this car? Why do I have to keep struggling to pay for something to get fixed and it is still not solved. Below, it ask for a date, but it is multiple dates, not just one. I have listed the first time it occurred. Thank you.

NHTSA ID

11544050

Incident

Mar 22, 2022

The contact owns a 2016 Hyundai Sonata. The contact stated that the vehicle failed to start. There was no warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed that the engine had failed. The vehicle was repaired; however, the failure recurred. The vehicle was taken back to the dealer, where it was diagnosed that the high-pressure fuel pump had failed. The contact related the failure to an unknown Hyundai Extended Warranty that had expired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was 98,000.

NHTSA ID

11540796

Incident

Nov 15, 2022

Mileage

98,000 mi

Hybrid system failure, car stopped in the middle of traffic

NHTSA ID

11524261

Incident

May 28, 2023

My car idles very rough at times, and sometimes when idling, it dies out. At times it is difficult to even start as if it's not getting the electrical signal to the engine. Hyundai replaced the fuel pump, but that did not fix the problem, but cost $1,200. No warning messages. Two other automotive companies also did a diagnostic tests, but couldn't find the problem as it seems it has to be tested WHEN IT IS ACTING UP. It died on me far from home a week ago, but eventually restarted. I'm afraid to drive it especially at night as it died when idling at a light and almost didn't restart.

NHTSA ID

11506298

Incident

Jan 31, 2023

2016 Hyundai Sonata (not part of any recall) driven short distance on expressway had "check engine light" come on. Pulled off of expressway and checked under hood...No visible issues. Chose to return home via side streets as car was riding rough and having problems with acceleration at that point. Short while later, heard loud noise and saw smoke coming from under hood. Pulled to the side of the road and exited car. Was told by bystander that car was on fire. Called Fire Dept, by the time of their arrival, entire front end ablaze, tires and body melted. Thankfully, fire extinguished before any explosion or damage to neighbor's property occurred. Vehicle was a total loss.

NHTSA ID

11490776

Incident

Oct 14, 2022

The engine is consuming oil at abnormal rate. After receiving an oil change at a credible business the car is out of oil in a week. Hyundai will not check for oil consumption if the mileage is above 85k miles. Myself and my children can be stuck on the side of the road for engine failure due to the lack of oil. Express oil has stated this is not normal and a cause for concern. There are no warning signs for this problem. Only awareness from the performance of the cars decline to run properly.

NHTSA ID

11468340

Incident

Mar 11, 2022

My oil seems to be consumed really quickly! I get a full synthetic oil change and then my engine sounds strange and check the oil and there's no more oil in there! This is after less than 1,000 miles after the oil change! It's very expensive that every few months I need to go and get a new oil change, it's supposed to be every 6 months or after 5,000-7,500 miles with full synthetic but it only last about 700 miles before it starts to start to disappear! I'm scared it will cause my engine to get ruined and make a fire! This has been going on formore than 2 years now.

NHTSA ID

11457522

Incident

Mar 1, 2021

my 2016 Sonata SE vin #[XXX] has a engine recall, Hyundai gave me a lifetime Warranty of the engine and power train. the Sonata has 84577 miles on the engine and is using 1 QT of oil per 1,000 miles. took the car to Bentley Hyundai in Huntsville ,Al. for an oil change and to see what they will do about the oil issue. I'm to bring the car back to them in 1,000 miles for them to check out how much oil the car is using. I was told that even with the lifetime Warranty of the engine and power train that with the engine using a quart of oil that Hyundai won't do many thing to take care of the problem. If the engine was given a Lifetime warranty by Hyundai why won't they do any thing to correct the oil problem. Thanks [XXX] INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

NHTSA ID

11453245

Incident

Jan 31, 2022

I have been going to the dealership since July as my engine light was not shutting off. I kept being told that there were no loaner cars and that they could not fix the problems I was having kept putting a band aide on the issue and saying that I would have more problems. They told me the cat converter would need to be replaced but it was an engine recall issue. They had a loaner car for me for one day told me it was fine that it would probably go again I had them check the car again and they filled the oil and sent me on my way. Now I was on the side of the road with no car and am now being told they can’t work on my car until March which since I have been seeing them for 4 months now for the same problem that just got worse you would think they would try to help me. Instead they told me to go somewhere else turn in my dead car or I have to tow it and then tow it back in March. I can’t afford this right now it is terrible and there are no cars out there they are so expensive. Please help me I am very poor and have 2 jobs that require me to drive.

NHTSA ID

11444067

Incident

Dec 16, 2021