Hyundai Sonata knocking problems

Filed Oct 29, 2026 · Engine, Steering · FL

I am filing a formal safety complaint regarding severe vehicle instability, structural safety risks, and dealership workmanship negligence following a federal safety recall engine replacement. My vehicle received a new engine block under a federal campaign at a local dealership. Immediately upon picking up the vehicle, the front suspension developed a severe, heavy mechanical knocking and bumping noise over road surfaces under 20 mph, making the vehicle structurally unstable and hazardous to drive. To perform this engine swap, technicians were physically required to drop the front subframe framework and disconnect the lower suspension linkages and steering column components. The dealership is actively trying to deflect safety accountability for an assembly error. They issued a new estimate attempting to charge me over $3,200 to replace the entire front strut and rear shock assembly, claiming it is a 'pre-existing wear-and-tear' issue due to mileage. However, I hold the dealership's official Multi-Point Vehicle Inspection report from when the car was first dropped off for the engine failure three weeks prior. In that mandatory baseline safety report, their own technician thoroughly checked the under-carriage and officially marked my 'Shock Absorbers / Suspension' and 'Steering Gear Box / Linkage and Boots' as PASSED with green checkmarks. This objective paper trail proves the front chassis was tight, silent, and structurally safe before the repair. The safety hazard was introduced solely during the dealership's engine reassembly. The Service Manager explicitly refused to step out of his office to address this safety complaint, and the dealership released a compromised, structurally unsafe vehicle to a consumer. I request a formal federal safety investigation into this branch's safety compliance regarding recall implementation.

Filed Oct 28, 2026 · Brakes, Electrical · CO

On Wednesday, October 21, 2026, our 2015 Hyundai Sonata with the 2.4L Theta II GDI engine suffered a sudden, complete engine seizure while traveling about 75 mph on I-25 Southbound near Castle Rock, CO. A family member was driving. Warning lights across the car began flashing, the engine made a loud grinding noise, and the brakes stopped working. Over a long distance, the driver was able to get the car onto the shoulder and bring it to a stop, then engage the parking brake. There was no collision and no injuries, only because traffic was light. The car was towed to a repair shop, then transferred to a second shop, which determined the engine had seized and requires full replacement. This vehicle is covered by Hyundai's Theta II GDI engine campaigns for connecting rod bearing failure. On October 26, 2026, Hyundai told us the Knock Sensor Detection System software update (Campaign 953) was never completed on this vehicle and declined coverage. Neither we nor the prior owners, who are family members, recall receiving any notice of this campaign. All previous check engine lights were diagnosed and repaired at independent shops, including an intake manifold replacement in April 2024, and no shop ever identified an open engine campaign. A full engine seizure at highway speed, combined with the loss of braking, creates a serious crash risk for the driver and surrounding traffic.

Filed Oct 23, 2026 · Engine · TX

Recall 162 bearing water I came to a stop sign n my car died and caused the engine to kick n wen I started it it was knocking

Filed Oct 14, 2026 · Engine, Fuel system · MS

A franchise dealership performed a federally mandated safety recall service (ECM Software Update) and a knock sensor replacement on this 2015 Hyundai Sonata 2.0L Turbo. To perform these specific repairs, the technician had to work directly around the intake and turbocharger assembly workspace. Immediately after picking up the vehicle, it suffered a sudden and dangerous loss of power and refused to accelerate normally on the highway, creating a severe traffic hazard. Upon an immediate emergency inspection by the same service center 5 days later, the dealership documented in writing that the turbocharger intercooler hose clamps were completely off/unfastened. Because the technician left the clamps disconnected, the turbo lost sealed pressure, failed completely, and began dumping high-pressure engine oil backward through the air filter intake box. The service center is now refusing to take responsibility for the mechanical safety failure directly caused by their technician's recall repair negligence.

Filed Oct 13, 2026 · Engine · FL

Hyundai Motor America is explicitly refusing to honor the mandatory safety recall and lifetime warranty extension for a catastrophic rod bearing failure on my 2015 Hyundai Sonata (VIN [XXX]). The engine suffered a sudden internal connecting rod bearing seizure while operating, causing a complete loss of motive power and creating an immediate hazard. Hyundai Corporate Escalations issued a blanket denial solely because the vehicle carries a rebuilt title. However, the vehicle's official Hyundai portal confirms that Service Campaign 953 (the Knock Sensor Detection System software update) was successfully completed on XXX. The engine failure matches the exact factory manufacturing defect (internal oil starvation from manufacturing debris) that is the subject of the In re: Hyundai and Kia Engine Litigation. The external collision history that led to a structural/rebuilt brand has absolutely zero mechanical correlation to a sealed, internal crankshaft block defect. Hyundai is acting in bad faith by using an unrelated title status to evade a federal safety recall mandate and escape liability for a dangerous, stalling powertrain defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 5, 2026 · Engine · UT

I was driving on the freeway about 100 miles outside of Boise, ID when the vehicle went into limp mode and a flashing check engine light came on. I had it towed to the Hyundai dealership in Boise where they ran a diagnostic check and it came back with a P1326 code, which is the issue related to the engine/ball bearings. They said it passed the bearing clearance test (BCT) so they updated the software and gave the car back. I picked it up a week later and while driving it from Boise to Salt Lake City (where I live), it went into limp mode again with a flashing check engine light. This happened about 100 miles north of Salt Lake City. I had it towed to a dealership in Murray. They indicated it passed the BCT again, but they replaced the knock sensor and did an oil change and gave the car back. I picked it up, and the next day, while on the freeway, the same thing happened again. I took it back to the dealership. They indicated the knock sensors they just installed the day before needed to be updated, so they updated the software for the knock sensors. I just picked it up, and within 45 seconds of being on the freeway, it went right back into limp mode with the flashing check engine light. This has happened 4 times now, on the freeway forcing me to immediately get over, and I have almost gotten into two separate accidents because of this. Hyundai says they will not replace the engine because it keeps passing the BCT. The vehicle is not safe to drive and it is likely causing irreparable damage to the other systems of the car.

Filed Oct 4, 2026 · Engine · UT

While driving on the freeway, the check engine light started flashing and the gas pedal became useless. This put the driver and the passenger of the car in massive danger as they could no longer accelerate on the freeway. Luckily, they were able to get off the freeway without causing an accident. Upon reading the code at an auto shop, they discovered that it was P1326 or a knock sensor issue. This malfunction caused the car to go into limp mode and put the passengers in serious danger. Several calls to the Hyundai Service Center were made yesterday (Saturday, October 3rd). However, not one was ever answered. They hope to be able to get the car to the dealership's service center as soon as possible, but the earliest appointment online is multiple weeks away. This same car was recently at the dealership service center for an internal engine oil consumption problem and thoroughly inspected. The car is up to date on all software and recalls. Even though a valve cover replacement fixed the oil consumption issue, the owners are now having even worse issues. This is the only car for a married couple who are both working and going to college full-time. This issue has been a severe complication to their scheduling, and they were put in harm's way on the freeway.

Filed Sep 28, 2026 · Engine · FL

Factual summary * Vehicle: 2013 Hyundai Sonata * VIN: [XXX] * Incident date: XXX * Failure: Sudden knocking noise, immediate check‑engine illumination, loss of power, and catastrophic engine failure; vehicle towed to Allen Turner Hyundai, 6501 Pensacola Blvd, Pensacola, FL 32505. * Recall: My VIN appears on Hyundai’s engine recall list; the recall notice was issued before the vehicle received a rebranded title. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 22, 2026 · Engine · CA

I am reporting an unaddressed, critical safety defect involving the Theta II engine in my 2017 Hyundai Sonata. The engine has developed a severe internal metallic knocking noise consistent with connecting rod bearing failure—the exact manufacturing defect associated with Hyundai's major engine recall campaigns (such as Recall 198 / Campaign 966)

Filed Sep 15, 2026 · Engine · TX

The vehicle experienced a Theta II engine failure at under 57,830 miles while driving on northbound [XXX] near the [XXX] Parkway U-turn in [XXX]. The engine made a loud noise and lost power. I was able to coast to the far right side of the U-turn under the bridge. I called HERO (Austin's emergency roadside assistance). They responded, determined it was not a battery issue, and pushed the vehicle to the Southern Leisure Spa parking lot on the southbound side of the road. The vehicle was then towed. The vehicle is equipped with the KSDS (Knock Sensor Detection System) software update, installed as part of Hyundai's remedy for this known defect. Despite KSDS being installed, the engine failed due to connecting rod bearing wear, consistent with the documented Theta II defect. A Hyundai dealership confirmed KSDS was installed but denied the warranty claim, citing maintenance records. The vehicle is available for inspection upon request. The Theta II engine defect has been the subject of prior the federal safety agency investigations and Hyundai recalls. This complaint is filed to document another failure of the same defect in a vehicle with the manufacturer's remedy installed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)