2018 Hyundai Santa Fe Sport: engine stalls while driving

Filed Oct 27, 2026 · Engine · PA

This vehicle has been suffering from substantial engine oil consumption, burning oil at an alarming and unsafe rate. I have repeatedly brought the vehicle to Washington Hyundai to address this under the engine class-action lawsuit terms, but the dealership continues to run repetitive tests without a resolution. This is a critical safety issue. Excessive oil consumption poses a severe risk of sudden, catastrophic engine seizure or stalling while operating at high speeds on the highway.

Filed Sep 15, 2026 · Engine · NE

My 2018 Hyundai Santa Fe Sport (2.4L Theta II GDI, VIN [XXX], approx. 110,000 miles) has suffered a chain of engine and emissions-system failures that create a loss-of-power safety hazard. At about 80,000 miles, Hyundai replaced the original engine under warranty for excessive oil consumption, a defect Hyundai has acknowledged across the Theta II engine family. After only about 20,000 miles on that replacement engine, the catalytic converter failed and set a P0420 code. The vehicle now bogs down, hesitates, and loses power under acceleration. This is dangerous when merging or accelerating into traffic, where a sudden loss of power raises the risk of a collision. A restricted or failing catalytic converter causes exhaust backpressure and abrupt power loss, and the underlying oil consumption also risks low-oil engine damage and stalling. A catalytic converter should last far longer. This premature failure is consistent with the well-documented Theta II pattern in which engine oil consumption contaminates and destroys the converter substrate. It indicates the replacement engine Hyundai installed is itself consuming oil and damaging downstream exhaust and emissions components. I reported this to the dealer and to Hyundai. Hyundai declined to cover the catalytic converter, treating it as unrelated, even though its own warranty engine replacement is the direct cause. I am filing so this safety-related failure is documented. No crash, fire, or injury has occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 17, 2026 · Engine · TN

The Hyundai Theta engine is a bad design that has many recalls, a history of oil consumptions, and breakdowns that leave consumers in danger, on the roadside, and out of money. This engine has a design that causes worn engine components and high oil consumption causing reduced engine power, ruined spark plugs, and engine damage with no recourse as a owner. Recently, my family member had a hesitation that causes the car to run rough and display a check engine light. She was in traffic and the vehicle was stopping. Had this been on the interstate it could have been deadly. This IS NOT UNCOMMON for these vehicles. A quick Google search is nationwide proof of an issue with these vehicles and engines that the government needs to hold Hyundai accountable. This particular vehicle has been assessed by a Hyundai and confirmed it is consuming oil at a higher rate than normal, as many other owners have documented. With this most recent issue of stalling out, the mechanic indicated that excessive oil consumption entering the spark plug port has fouled the spark plugs as the design of the engine is flawed. The oil consumption was discovered at approximately 99,000 miles and several steps were completed to "fix" and confirm the issue. There is no "real fix" to the issue due to the inherent design of the motor. Again, this is not a new issue with these cars and there should be recourse that holds Hyundai accountable for bad and dangerous engines. The check engine light did come on as the vehicle began to stall and run rough in traffic.

Filed Jul 17, 2026 · Engine · TX

The engine on this vehicle suffers from a severe oil consumption defect that was first officially reported to the authorized dealership on February 3, 2025 at approximately 90,000 miles while under the factory powertrain warranty. The vehicle completely empties its engine oil supply in under 1,000 miles of normal driving. Running entirely out of oil within such a short interval poses an imminent, extreme risk of sudden engine seizure, catastrophic mechanical failure, and sudden stalling at highway speeds. The manufacturer and dealership have physically documented this rapid depletion of oil over a 17-month period but are refusing to replace the defective components, instead attempting to force this unsafe vehicle back onto public roads for repetitive driving tests.

Filed May 25, 2026 · Engine, Fuel system · KY

2018 Hyundai Santa Fe Sport. Purchased January 2026 took to Oxmoor Hyundai Service Center March 2026. February 2026 began using oil at a measured rate of 700 miles per tank of oil. Used 3 full tanks of oil within the month of February. Oil lights and engine lights on and off and flashing during this time. March 8, 2026, engine light flashed and then stayed on continuously. Engine shook and stuttered and made a loud noise. Engine stalled while I was driving at 35-40 miles per hour. I was able to continue driving to my home with the stuttering and stalling. The next morning I drove it to the Oxmoor Hyundai Service Center. I told relayed the timeline of all symptoms I had experienced over the 2 month lifetime of my ownership. They did not attempt to reproduce the issue. They only entered "shakes in reverse" as the customer provided issue on the intake information. Service Center performed diagnostic, found cylinder misfires on cylinder 2 and cylinder 4. Replaced spark plugs to resolve Cylinder 2. Cylinder 4 continued to misfire. Used Borescope and found broken valve. They did not address the scoring on the cylinder of the valve. Recommended engine replacement. Advised it would not be covered under a warranty because the rod did not break. The oil consumption was proven with documentation from multiple Valvoline visits and the vertical scoring was present on the cylinder with the broken valve in the borescope photo. The Service Center refused to do a Boring Clearance Test or any other test that would prove the engine should be covered under an extended warranty or class action settlement. It wasn't until I reviewed HMA documents uploaded to the BBB Arbitration, that I realized that the information I initially gave to the Service Center of all the symptoms with timelines had not been entered into the system for diagnostic review by Techline. Arbitrator denied my claim under the theta settlement because the rod had not broken yet, BUT she said my engine was defective.

Filed May 14, 2026 · Fuel system · VA

Took car to dealer to have oil changed on april 29, 2026 and was told they had also preformed a software update, service campaign 9c2. Everytime since that day after the car has set for a little while and the car is restarted driven it stalls and surges really bad several times lasting for several minutes. It also can do this at random at anytime but not constant like it does when first started. This is very dangerest for obvious rasons and needs to be fixed. Although there is others reporting the same problems on line and a person making the same complaint while I was wating at the dealership. They say "they are unaware of the problem and I will have to leave my car for up to three days or more to have it checked out and then they will let me know what needs to be done” and what the cost will be. I only have the one vehicle and they would not provide a loaner vehicle so needing my car every day I can not do without it. Due to the fact that hyundai refuses to acknowlage the problem. There really needs to be a recall to have this problem fixed.

Filed Apr 7, 2026 · Engine, Fuel system · TX

My 2018 Hyundai Santa Fe Sport equipped with a Theta II GDI engine began exhibiting excessive oil consumption, engine knocking, and cylinder misfires consistent with the known Theta II engine defect covered under the Hyundai class action settlement. Prior to the failure, the check engine light illuminated and I experienced repeated misfires and audible engine knocking. The vehicle required frequent oil additions between oil changes due to excessive consumption. The vehicle was taken to an authorized Hyundai dealership where a diagnosis confirmed a burnt valve inside the cylinder head. The dealership recommends replacement of the cylinder head or complete engine replacement to correct the issue. The dealership performed a bearing failure test and attributed the burnt valve to carbon buildup. However, excessive oil consumption in a GDI engine directly accelerates carbon buildup on intake valves, as burning oil deposits carbon on valve surfaces preventing proper seating and causing overheating and valve failure. The carbon buildup is therefore a consequential result of the Theta II oil consumption defect, not an independent cause. The safety risk is significant as engine misfires and knocking while driving create unpredictable loss of power and potential for stalling in traffic. The vehicle is currently not reliably operable. The manufacturer has been contacted regarding coverage under the Theta II settlement. The component is available for inspection upon request at the servicing dealership

Filed Mar 18, 2026 · Engine · FL

I am reporting a serious safety concern involving a 2018 Hyundai Santa Fe Sport with approximately 132K miles. While driving at highway speed, the vehicle suddenly lost power/velocity and the engine light flashed. This created an immediate safety hazard, as maintaining speed is critical in highway traffic. Within seconds, the vehicle regained power and the warning light turned off, giving the impression that the issue had resolved. Shortly afterward, while exiting the highway, the vehicle began shaking and felt as though it would stall but was able to drive home less than one mile. A mechanic retrieved misfire codes for cylinders 2 and 4. Further inspection revealed internal engine damage in cylinder 4 requiring major rebuild. A full deconstruction revealed that one of the valves in cylinder 4 had partially broken. This failure occurred with little to no warning and involved a sudden loss of power at highway speed, which could have resulted in a serious accident. The vehicle’s warning systems did not provide adequate or persistent alerts prior to significant engine failure. Over the last 6 months it began consuming oil frequently requiring weekly checks, however no warning systems or errors to indicate an underlining concern. Based on research, similar Hyundai vehicles have documented issues involving excessive oil consumption and internal engine damage without sufficient warning. This raises concerns about a potential safety defect affecting engine performance and failure detection.

Filed Jan 12, 2026 · Brakes, Electrical · 160,000 miles · AR

The contact owns a 2018 Hyundai Santa Fe Sport. The contact stated that while driving at 25 MPH and approaching a stop, the vehicle stalled. The battery, check engine, and oil warning lights were illuminated. The contact stated that the failure was related to the federal safety agency Campaign Number: 22V810000 (Service Brakes, Hydraulic). The vehicle was towed to the local dealer, where an unknown diagnosis was provided. The vehicle was not repaired. The warranty claim was denied. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 160,000.

Filed Oct 7, 2025 · Engine · MA

I own a 2018 Hyundai Santa Fe Sport. I leased it new, then purchased outright in May 2022. I had no issues with my vehicle. I maintained it regularly. Had appropriate interval oil changes. At no time from 4/2018 to 6/2025 did I have any knowledge of any issues with the engine in my vehicle & neither Hyundai nor the dealership contacted me in any manner to notify me of an issue with my engine. On or about October 2024, my check oil light came on for the first time in 6 years. I do not drive much because I work, & have worked, from home since July 2020. I took my car to my mechanic. He added almost 4 quarts of oil. I returned two weeks later & he changed oil. He saw nothing that caused him suspicion. He suggested I check my oil levels. Extreme oil consumption continued. My check oil light NEVER came back on. No other lights came on until 10/6/2025. I drove minimally. In July, 2025, I discovered my vehicle has a known defective engine. I uncovered multiple lawsuits against Hyundai regarding the defective engines. On 9/12/2025, I sent a Massachusetts General Law 93A Demand Letter mailed Certified Mail to Hyundai & dealership. On Oct. 6, 2025 at approx. 11:30 am, I turned on my car & without warning, my car immediately began shaking violently & vibrating & stalling - IN PARK. The check engine light began to flash intermittently in PARK. I drove my vehicle 7 miles to my mechanic (praying the whole time my car would not blow up with me in it); the car violently shook & vibrated the entire 7 miles. The check engine light changed to solid & acceleration was almost non existent. I am waiting for my mechanic to most likely give me bad news. Neither Hyundai nor the dealership have yet responded to my MGL 93A Demand Letter.

Filed Jul 14, 2025 · Engine · MD

While I was dropping on the highway my vehicle suddenly slowed down when and the engine started shaking when I approached around 40mph and the check engine light started flashing. After checking I’m getting the error codes P1326 and P0014. I’m not unable to go past 40mph and the vehicle starts stalling when I approach that speed which is incredibly dangerous depending on what road I’m on. I’ve had zero issues with this vehicle previously and have always had regular maintenance. After researching other Santa Fe sport have had identical issues and there are recalls for other years but my year 2018 was skipped for some reason even though it’s clearly affected.

Filed May 6, 2025 · Engine · CA

I’ve got a 2018 Hyundai Santa Fe Sport with a Theta II engine that’s failing—burning oil way too fast, coolant mixing in the cylinders, and throwing a P0304 misfire code. It’s been undrivable since late April 2025, and I’m worried about safety because the misfire and engine failure risk could cause it to stall on the highway, putting me and others in danger. It shakes when I try to drive, which feels unsafe. A Hyundai dealer confirmed the issue, finding coolant in the cylinders and the misfire, with no visible oil leak. Oil change receipts show the oil disappearing over a few weeks. The manufacturer reviewed my case but denied the warranty claim, saying it’s not covered since I’m a second owner and it’s not a rod bearing issue, even though the 2021 Theta II settlement should apply to this. The seller didn’t disclose the engine’s defect history when I bought it in 2023. The check engine light came on in early April 2025 with the misfire code, and I noticed the oil issue then. It’ll be out of service over 30 days by mid May 2025, so I’m taking legal action.