2016 Hyundai Sonata fuel system problems

Filed Aug 6, 2026 · Engine, Fuel system · NC

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 the federal safety agency’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)

Filed Jun 15, 2026 · Engine, Fuel system · 149,000 miles · WI

The contact owns a 2016 Hyundai Sonata. The contact stated that while driving approximately 60 MPH, the vehicle suddenly shut off with the message "HEV System Failure" displayed. The driver safely pulled over to the side of the road and restarted the vehicle. A towing truck arrived on the scene and reset the diagnostic codes before towing the vehicle. The vehicle was towed to the local dealer. The dealer retrieved several diagnostic trouble codes; however, the dealer was unable to determine the cause of the failure. The vehicle was test-driven but the failure was not duplicated. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The failure mileage was approximately 149,000.

Filed Apr 17, 2026 · Engine, Fuel system · AZ

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.

Filed Apr 17, 2026 · Engine, Fuel system · AZ

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.

Filed Mar 17, 2026 · Engine, Fuel system · FL

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.

Filed Feb 1, 2026 · Engine, Fuel system · DE

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

Filed Jan 19, 2026 · Engine, Fuel system · IL

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 the federal safety agency 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.

Filed Oct 10, 2025 · Engine, Fuel system · FL

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.

Filed Jun 8, 2025 · Engine, Fuel system · IL

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 the federal safety agency investigate repeated hybrid system faults and warranty denial patterns in Korean-manufactured Sonata Hybrids.

Filed May 20, 2025 · Engine, Fuel system · NJ

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.