Kia Niro overheating problems

Filed Oct 30, 2026 · Engine · TX

Second failure of the EGR cooler on this vehicle in under 90 days. Kia's own Pitstop PS730 (May 2022) identifies internal leakage of the EGR cooler on 2017 to 2022 Niro HEV as the cause of coolant loss, random misfires, and overheating. First failure: coolant tracked through the intake into the cylinders, all-cylinder misfires and loss of power, repaired by Crain Kia of Fayetteville AR on RO 1436350, picked up September 4, 2026, customer paid $1,931.52. Second failure: on October 30, 2026 the same dealer confirmed on video that the replacement EGR cooler it installed September 4 had failed and was leaking coolant, under eight weeks after installation. Symptoms were sudden coolant loss and misfires on cylinders 1 and 4 while driving. The driver is a college student making 460-mile solo highway trips in this car. Loss of coolant and misfires at highway speed are a safety hazard. The failed component is at the dealer and available for inspection. Kia declined my first goodwill request on this repair under Kia Consumer Assistance case 26294863; a second request is pending following this repeat failure.

Filed Aug 6, 2026 · Electrical, Engine · VT

AC not working, recall SA512 is needed, Kia wont cover the cost of replacing electrical components. Thermal Runaway / Fire Risk: The broken compressor prevents the battery thermal management system from cooling the main high-voltage lithium-ion battery package, creating an overheating hazard during driving or DC fast-charging. Sudden Loss of Power (Motive Power): Battery overheating can trigger a sudden "safe mode" or turtle mode, dropping your speed to zero unexpectedly on the highway.Impaired Driver Visibility: The lack of functional cabin heating prevents windshield defrosting, severely impairing the driver's ability to see the road safely.

Filed Jul 26, 2026 · Electrical, Engine · IN

My 2023 Kia Niro Hybrid EX has experienced multiple warning messages and unresolved concerns after previous repairs. After the first recall repair, I began receiving intermittent warning messages while driving. The messages appeared briefly and disappeared before I could safely document them. After a second repair, the transmission was replaced. Shortly afterward, the vehicle displayed an overheating warning. I returned to the dealership, but they stated they could not find a problem. While traveling out of state, on July 6, 2026, the vehicle displayed warnings indicating that the 12V battery needed to be charged. On July 8, 2026, the vehicle would turn on, but the engine would not start or operate. Multiple attempts to jump-start the vehicle failed, including using a portable jump pack, another vehicle, and assistance from a tow truck driver. The vehicle displayed warnings stating that the 12V battery needed charging, the battery was draining, and that the hybrid system needed to be checked. Because the vehicle could not be operated and I was stranded away from home, I am concerned about the reliability and safety of the vehicle. The vehicle has undergone multiple repairs, including a transmission replacement, but I continue to experience warning messages and a loss of confidence in the vehicle's ability to operate reliably. I am requesting that this issue be reviewed for possible safety concerns.

Filed Jul 20, 2026 · Body · 92,000 miles · CA

The contact owns a 2022 Kia Niro. The contact stated that a hardwired kill switch was installed in the vehicle, and the switch overheated to the point that the vehicle was unable to operate. An investigation was conducted by the contact, who touched a big box underneath the dashboard. The contact's hand was burned on the fingertips because the box was extremely hot. Water was run over the hand by the contact to heal the injuries, but outside medical attention was not sought. The dealer was notified of the failure and a callback was promised. A diagnostic test and the repair were not yet performed. The manufacturer was not made aware of the failure. The failure mileage was approximately 92,000.

Filed May 18, 2026 · Transmission · 140,000 miles · GA · crash · 2 injuries

The contact owns a 2024 Hyundai Niro Hybrid. The contact stated that while at a stop light the warning message "transmission overheating" had displayed and the vehicle did not drive forward. The contact attempted to push the vehicle offer the road when suddenly the vehicle accelerated forward and drove on the opposite side of the over a curb and drove into oncoming traffic and crashed head on into a second vehicle. The vehicle the drover over a curb and down an embankment and crashed. The failure mileage was 140,000.

Filed Mar 31, 2026 · Engine · PR

The vehicle has a recurring P0420 code (“Catalyst System Efficiency Below Threshold Bank 1”). A boroscope inspection at Ricardo Caballero Kia Santa Isabel (invoice #[XXX] dated December 5, 2025) confirmed internal disintegration of the catalytic converter, with physical pieces of the catalyst falling out when the exhaust pipe was removed. This failure appears related to Recall 23V534 (SC276) and TSB PS709 (overheating / coolant boiling issues in 2017-2022 Niro Hybrid models). Motorambar, Inc. (official Kia distributor in Puerto Rico) has ignored my warranty claim since December 2 and December 22, 2025 (more than four months). Motorambar is now refusing to authorize a courtesy loaner vehicle at the dealer Ricardo Caballero Kia Santa Isabel, claiming the tests will take less than 5 days. This leaves me without transportation. The catalytic converter is fully covered under the Federal Emissions Warranty (8 years / 80,000 miles). I request that the federal safety agency investigate this as a potential safety and emissions defect and require Kia / Motorambar to: 1. Immediately repair or replace the catalytic converter under warranty at no cost. 2. Provide a courtesy loaner vehicle during the repair. 3. Reimburse previous diagnostic costs of $449.17. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Mar 26, 2026 · Electrical, Fuel system · VA

I own a 2020 Kia Niro PHEV. In October 2024, my dealership performed Technical Service Bulletin SA512 on my vehicle addressing the inverter coolant system. I was not informed at that time that the issue was likely to recur or that periodic maintenance would be required. In March 2026, the inverter coolant warning light returned. I brought the vehicle back to the dealership, where I was told the coolant had crystallized. The dealer confirmed this is a known recurring issue with this vehicle and stated it would need to be flushed approximately every two years since we drive relatively low miles per year (despite driving every day). I was not warned of this at any point. Furthermore, many owners likely drive it short distances every day since it is a plug-in electric vehicle. Kia denied goodwill coverage and I paid out of pocket for the repair. When I contacted Kia Customer Care, representatives gave conflicting information. One confirmed SA512 was performed as a service campaign, another stated it was only a TSB and declined coverage since my car is out of warranty (even though the warranty should still cover the battery and this is an electrical issue). A total case specialist I was assigned to said she would talk to the dealer and call me back but never did. The inverter cooling system is safety-relevant as it prevents the battery from overheating. The problem was confirmed and repaired by the dealership. The component is no longer available for inspection as the repair has been completed. Kia's issuance of SA512 suggests this is a known design issue affecting multiple owners of this model, and they informed the dealership that they could not cover the cost because if they did so, they would have to cover everyone with the same problem (again implying that the issue is quite widespread.)

Filed Mar 18, 2026 · Engine · VT

-Car was leaking or burning coolant causing engine to overheat. -Car was diagnosed with: Exhaust heat exchanger is leaking coolant and needs to be replaced. After costly repair, car continued to leak coolant and overheated. -Car was taken back to the dealership and diagnosed with: Engine Assembly - Long Block - Replace | Engine long block needs replacement due to coolant in the oil. This was at a certified Kia Dealership. No insurance reps or police were involved. An engine light has come on a couple of times over the years that was interpreted to mean replacing the gas cap. After replacing the gas cap, the engine light didn't come back on. My safety was impacted as a person living in a cold, rural state to have a sudden mechanical failure where I couldn't run the heat and had to stop the car immediately.

Filed Mar 14, 2026 · Electrical, Engine · NY

While traveling from upstate New York, the vehicle displayed an engine overheating warning shortly after startup while the engine was still cold. Because I was away from home, I stayed overnight and the next morning took the vehicle to a Kia dealership for inspection. The dealership inspected the vehicle and diagnosed a problem with the exhaust heat recovery system pipe. According to the service department, coolant is leaking internally through this component and is being burned in the exhaust system. The cooling system was pressure tested and held pressure externally, indicating the coolant loss is occurring internally through the exhaust heat recovery system rather than from an external leak. This condition can cause coolant loss and overheating while driving. If the engine overheats while the vehicle is in operation, it could create a safety risk due to sudden loss of power or engine damage. The dealership confirmed the diagnosis after inspection and testing and provided a repair estimate to replace the affected exhaust heat recovery system component. The overheating warning message was the first symptom observed prior to diagnosis. The problem was confirmed by the dealership after inspection and testing. This issue may indicate a defect in the exhaust heat recovery or thermal management system used in this hybrid vehicle, as coolant is entering the exhaust stream internally rather than leaking externally. If this type of failure occurs in other vehicles, it could lead to overheating while driving and potential engine damage.

Filed Dec 31, 2025 · Engine · WA

Failed/leaking coolant heat exchanger which is integrated into the rear catalytic converter assembly. This seems to be a well-known issue with 2017-2020 Kia Niros. Leaks cause overheating of the engine or no heat in the vehicle and potential blown head gaskets. This issue has been confirmed by an independent service center. Car itself gave no messages or warnings regarding the leak.