2019 Hyundai Sonata: engine overheating

Filed Aug 18, 2026 · Engine · 140,000 miles · FL

The contact owns a 2019 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the vehicle experienced severe overheating and excessive oil consumption. The contact also stated that there was a misfire in the engine even though the spark plugs and ignition coils were replaced. Due to the failure, the vehicle could not be driven with the air conditioning activated. Additionally, the engine was knocking and shaking abnormally, causing an oil leak and a smoke odor due to the oil burning. The vehicle was taken to a dealer, where an engine replacement was recommended. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 140,000.

Filed Aug 13, 2026 · Engine · NJ

On January 26, 2026, my 2019 Hyundai Sonata SEL suddenly became inoperable overnight. The vehicle had been operating normally with no warning signs—no check-engine or oil-pressure light, abnormal engine noise, overheating, loss of power, or other indication of an impending failure. The following morning, the engine would not start. The vehicle was towed to an independent mechanic on January 28, 2026, who determined that the engine was locked/seized. On February 11, 2026, it was towed to Wayne Hyundai for further diagnosis. The vehicle had only 51,533 miles and had received Hyundai’s Knock Sensor Detection System (KSDS) update. Hyundai denied warranty coverage, citing engine sludge, despite my providing a complete service history after resubmiting the missing receipts I had previously misplaced. My primary concern is safety, not the warranty dispute. A sudden engine seizure without warning could cause an unexpected loss of propulsion or create a dangerous situation if the engine fails while the vehicle is being driven. This concerns me because Hyundai Theta II engines have previously been associated with engine seizure and stalling, including issues addressed through The Hyundai Theta II Engine Settlement: and subsequent litigation involving certain 2019 Sonata vehicles. I respectfully request that the federal safety agency investigate whether a continuing or insufficiently addressed engine defect exists in affected 2019 Hyundai Sonata vehicles, particularly sudden engine seizure/no-start failures occurring without warning. I also ask the federal safety agency to examine whether existing recalls, campaigns, software updates, warranty extensions, and other remedies adequately protect owners when an engine fails suddenly before the KSDS system provides a warning.

Filed Jun 20, 2026 · Engine · VA

The engine is the component or system failed or malfunctioned, and it is available for inspection upon request. Sudden loss of engine power while driving, including during highway speeds or intersections, increasing the risk of a crash. Engine stalling or failure to accelerate, preventing me from safely maneuvering away from hazards. Overheating events, which resulted in complete engine seizure and an unexpected loss of vehicle control, all which can potentially causing catastrophic incident without warning. To include, the increased risk of collision, especially if the failure occurs during traffic, merging, passing, or emergency situations. It has been reported to CC Transmission Auto Repair and independent service center. It was previously inspected by Hyundai dealer. Check engine light present September 2025.

Filed Feb 27, 2024 · Engine · OK

We keep getting an engine light every 2-3weeks. That sets the engine in a safe mode (limp mode). The code comes up Knock sensor overheat. Tho inspecting the engine we have notice in that time frame the car is low 1-2qts oil. Once the oil has either been replaced or added to and code reset it drives normal. Again until 2-3 weeks and bam. A course now we know to check our oil. After hours of research, we see no recalls for our car. Tho many years back that have had the exact same issue. The issues also came to light when car hit around 80k miles.

Filed Nov 4, 2019 · Engine · 5,768 miles · GA

I purchased a 2019 sonata demo vehicle with 5,020 miles in june 2019. I removed the temporary tag and replaced with permanent tag on july 16. On july 20, while driving on the expressway at approximately 65mph, the engine overheating alert came on and the temperature gauge was on hot. I pulled over on the side of the expressway and waited for hours (in nearly 100 degree summer heat) to have a new vehicle towed to the dealership. The service department advised me that the water pump malfunctioned and caused the belt to tear. The service department could not provide a reason for why the water pump/belt malfunctioned on a new vehicle. The water pump and the belt were replaced after the service department had my vehicle for a about a week. The service department advised me that I should not have any further issues with the vehicle. The repairs were completed on 7/29/19. On august 16, I took my vehicle back to the dealership because it appears that the replaced/new belt is splitting/tearing. The service department advised me that there is nothing wrong with the belt, however, there is clearly visible evidence that the new belt is splitting also. I have attached a photo of the vehicle prior to the repairs; a photo of the new belt that is currently splitting; the original service repair document and the document of the service department advising me that nothing is wrong with the new belt. From the photo, you can clearly see that the new/replaced belt is splitting also and it is just a matter of time before the engine will overheat again and I will be on the side of the road waiting for a tow. Again, the service department did not have an explanation as to what caused the water pump/belt to malfunction and now they are denying that there is an issue with the replaced belt.