2018 Kia Niro Engine Problems

On April 21, 2026, Go Kia Renton performed an oil change on my 2018 Kia Niro Touring (VIN). The car was in perfect condition just two weeks earlier — North Seattle Transmission did a full service on April 6, 2026 at 283,649 miles with no issues noted. Later that night while driving, the red oil light flashed. I pulled over immediately and called AAA. AAA towed the vehicle from Belltown [XXX] ) at 12:11 AM on April 23 to my house then at 9:14 AM towed it straight to Go Kia Renton. The AAA driver found oil leaking all over his tow truck. The car now has a dead battery and is showing Hybrid Control System / Low Voltage DC/DC Converter and Engine Control System codes. This appears to be a sudden engine seizure caused by oil loss shortly after dealer service. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11735577

Incident

Apr 23, 2026

Just before Hurricane Helene, I brought my 2018 Kia Niro Hybrid to Asheville Kia (NC) after noticing coolant loss and white smoke coming from the exhaust. The dealership charged me $1,400 for a repair involving new gaskets and the EGR cooler. Within a month, the same symptoms returned. I returned to the dealership and explained I believed the original issue had not been resolved. I had done research and found reports of similar problems in other Niro Hybrids. I specifically mentioned the coolant heat exchanger as a possible source, but they dismissed my input and pushed a $3,500 muffler system replacement. I asked for diagnostic proof, and they initially showed a photo of the muffler with no visible leak. Later, they claimed a "small leak" was found during a pressure test — but the symptoms didn’t align. I then took the vehicle to John’s Kwik Lube in Spruce Pine, NC, where they confirmed the coolant heat exchanger was faulty — exactly what I had originally suspected. They repaired it with a simple workaround for under $200, and I’ve had no issues since. The faulty component (coolant heat exchanger) is not available for inspection, but I retained diagnostic records, pressure test results, and screenshots of the dealership’s estimate. I also documented that Kia’s quote system does not allow access to past service quotes, so I had to screenshot everything manually. The only symptoms were coolant loss and white smoke from the tailpipe, beginning shortly before the storm in September 2018, and recurring until the final repair later that year. The problem was confirmed by an independent mechanic, and partially acknowledged (though misdiagnosed) by the Kia dealership. No police or insurance inspection was involved. This situation posed a safety risk due to reduced visibility, potential engine overheating, and exposure to coolant vapors, especially during uphill driving. The issue is known among Kia owners and appears to be a recurring design flaw in the Niro.

NHTSA ID

11688703

Incident

Sep 30, 2024

Known issues with wiring cause check engine light to come on and also now the door open sensors to stay on. Just paid $800 for a known issue to the wiring that a Kia technical bulletin wss issued for, however the cost was left to the customer.

NHTSA ID

11638518

Incident

Jan 25, 2025

Internal combustion engine coolant leaking out exhaust. The heat exchanger located in the catalytic converter system is leaking, leading to the ICE coolant draining. This leads to the engine overheating, and damage. Signs of the issue started with the coolant level lowering quickly, then the car heater stopped working. This confirmed by an independent mechanic.

NHTSA ID

11622855

Incident

Oct 30, 2024

The contact owns a 2018 Kia Niro. The contact stated that upon starting the vehicle, the vehicle was shuddering and failed to start. The battery charge was low. The HEV warning light was illuminated. The vehicle was taken to the local dealer but was not diagnosed or repaired. The dealer informed the contact that a field expert would be determining the cause of the failure. The manufacturer was not contacted. The failure mileage was 140,000.

NHTSA ID

11594151

Incident

May 8, 2024

Mileage

140,000 mi

Coolant leak within the heat exchanger of the catalytic converter. Increases likelihood of overheating and engine damage. Especially when driving long distances, or within heavy traffic. Increases emissions as burning off coolant within exhaust.

NHTSA ID

11578765

Incident

Mar 18, 2024

Fire warning recall notice issued in July 2023. Follow up with both Kia and with Kia dealership that I purchased the vehicle from still says that there is no fix to this problem. THE PRINTED CIRCUIT BOARD (PCB) IN THE HYDRAULIC CLUTCH ACTUATOR (HCA) MAY BECOME CONTAMINATED WITH FLUID. A FLUID-CONTAMINATED PCB MAY LEAD TO AN ELECTRICAL SHORT CIRCUIT, THEREBY INCREASING THE RISK OF AN ENGINE COMPARTMENT FIRE WHILE DRIVING. With the potential of a fire risk while driving, why is the manufacturer not required to remedy this situation in a more timely manner. It has been over 6 months since the recall was issued yet the manufacturer is allowed to continue producing vehicles but not required to repair those vehicles that may be affected and cause significant risks to the driver at potentially other property. NHTSA should mandate inspection and repairs of recalled vehicles which should take a priority to the manufacturing process. Vehicles with recalls should not be allowed to go without repair especially when accidents are imminent and life-threatening injuries may occur. Additionally, trying to get an appointment with a local Kia dealer where I purchased the car has a wait of well over a month for them to even inspect the car. Between Kia not taking care of their vehicles and their dealers not being able to service vehicles, NHTSA really needs to evaluate this and create remedies for the safety of the vehicle and the driver. Waiting over 6 months for a recall is frustrating, dangerous, and unacceptable. Manufacturers need to take responsibility for recall notices and repairs in a much more timely manner. Safety over profit should be a priority. On a personal note. I purchased my Kia Niro hybrid new in 2018. It is one of the best cars that I have purchased in my '76 years. I have had virtually no problems with the vehicle and was a big proponent of Kia, but their lackadaisical attitude on recall repairs as really put a damper on my respect for their management and

NHTSA ID

11567929

Incident

Jul 6, 2023

Nothing has happened yet, but I am very concerned about my car catching on fire due to the recall notice I received. I want it fixed ASAP!

NHTSA ID

11553924

Incident

Oct 13, 2023

Got the recall letter but kia dealer and customer service have no info about when the remedy will be available. This is a major issue as I need to sell the car now to use the cash for other urgent matters. Dont even think the dealer will give a decent wholesale amount or take them on a trade. It is lowering the value and decreasing the demand as its a safety hazard for the vehicle which isnt fair . How long are they legally allowed to drag this out with no compensation to all those waiting ? Is there a class action suit ? Thank you for your help ! [XXX] [XXX] or cell [XXX] . INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11551199

Incident

Sep 29, 2023

On March 28, 2023 the vehicle HEV warning light came on. I called the dealership where I was informed they did not have any mechanics available to look at it until August. No one to work on Hybrid. I then took it to a mechanic shop, And I was informed to take it to the dealer. I could not drive the vehicle. I called KIA, Temple Hills back, I was told if you tow the vehicle here it will just sit. April 8, 2023 had it towed to another shop, the mechanic stated he thought it was the battery, which I was informed hybrid has 3 batteries, to check with the dealer to see if they had them, or could order one. Called the dealership Temple Hills, stathat they had never heard of a battery for that car. I was told to call back next week, after he spoke with the parts dept. manager. I called back a week later, and was told they knew nothing about a Kia Niro, could not help. The mechanic looked for a battery at other shops, ebay. The one I Paid 600.00dollars for did not work. After being there for 1 month. I called Kia dealership Bowie Md. On June 6, 2023 spoke with Jacob, the advisor. The vehicle was towed there, Jacob refused to give me any updates on the vehicle after 1 month being there, just sitting. I would call him trying to get updates, he informed me that they only had one mechanic, just a whole lot of nothing, the vehicle could catch on fire. Another month passed and I went to the dealership, along with my brother. Jacob was not answering my calls/returning them. Vehicle just sitting there. Jacob, then said the mechanic that worked on the hybrid was out for surgery, he would be in touch. I asked for the Kia Corporate number, which I received. I contacted Kia, corporate on July 13, 2023, spoke with them several times, informing them that the vehicle was not operable, and I was still making car notes/ paying insurance on a vehicle that I was not driving. At the dealership now for 3 months. Jacob, not communicating I can email you documents/fax, all paperwork.

NHTSA ID

11549759

Incident

Mar 28, 2023

The contact owns a 2018 Kia Niro. The contact stated while driving at an undisclosed speed, the engine revved up. The contact stated that the accelerator pedal was depressed; however, the vehicle was slow to respond. Eventually, the vehicle shifted into gear and started to move. The contact stated that the check HEV and turn off engine error messages were displayed. The vehicle was taken to the local dealer, where it was diagnosed that a faulty engine clutch activator needed to be replaced. The mechanic informed the contact that the vehicle was not covered under a recall. The vehicle was not repaired. The contact stated that the failure was related to NHTSA Campaign Number: 23V534000 (Power Train). The manufacturer was not contacted. The failure mileage was approximately 120,000.

NHTSA ID

11548358

Incident

Oct 2, 2023

Mileage

120,000 mi

The contact owns a 2018 Kia Niro. The contact stated while driving approximately 65 MPH, the vehicle started shaking and vibrating abnormally. The contact stated that the accelerator pedal was depressed; however, the vehicle failed to respond as needed. The contact stated that the message "Engine Overheating - Request Service Now" and "Engine Control System" was displayed. The contact had taken the vehicle to an independent mechanic where it was diagnosed and determined that coolant had intruded into the engine block and the engine needed to be replaced. The vehicle had not been repaired. The contact attempted to contact the manufacturer but was unable to reach a Representative. The failure mileage was approximately 74,000.

NHTSA ID

11547172

Incident

Sep 15, 2023

Mileage

74,000 mi

HEV warning light on, car monitor says possible MCU failure. I just bought this car. This car is in perfect condition, no accidents all service actions in order but the warning lights make it seem like the electric engine is about to fail.

NHTSA ID

11526275

Incident

Jun 9, 2023

The car can slow down suddenly in the middle of traffic even if I accelerate. The engine has a problem according to the mechanics who was trying to fix my car twice without succes. The car does not hold coolant liquid for more than 15 minutes. It looks like the coolant is staying somewhere in the engine. It overheats too. Yes the car is available for inspection upon request. It's a high risk because the car can suddenly slow down in the middle of traffic or when leaving a light turned green. And the last time I drove it there a weird smell. Yes, an independant service center located at College Park Maryland informed me about the issue. The vheicle or compenent has not been inspected yet by the manufacturer, police, insurance representative or others. When the car starts slowing down in the middle of traffic, I feel a kind of vibration first on the gas peddale and comes up the engine light. This happened last month

NHTSA ID

11517087

Incident

Mar 18, 2023

On Kia Niro, there is a part called the Exhaust Heat Recovery System (EHRS). This part pumps coolant into the exhaust system. If this particular piece fails, coolant in then pumped into the exhaust, burned up, and exits through the tail pipe. This piece failed on my car, which lead to coolant being burned in the tailpipe without my knowledge, which ultimately lead to no coolant in the engine and overheating and breaking down on the highway. After a full engine replacement, my car is still rapidly going through coolant. I imagine that this could lead to a car fire. I still have the faulty part installed in my car, however I am looking to replace it asap. While not 100% confirmed, my dealer is "pretty sure" that piece is what is causing the rapid loss of coolant in my car. This piece has not been inspected by the manufacturer, police or insurance representatives. There were no warning lamps, messages or other symptoms to alert me to this problem. I only found out about this piece and its failure rate after a full engine replacement.

NHTSA ID

11502867

Incident

Oct 31, 2022

I WAS DRIVING ON THE FREEWAY. AFTER SLOWED DOWN AND STOPPED COMPLETELY, SUDDENLY IT LOSE POWER TO RUN. TRYING TO STEP DEEPER THE GAS PEDAL, BUT NO REACTION AT ALL. AFTER TURN OFF AND TURN ON ENGINE FEW TIMES, IT CAN RUN AGAIN, BUT THIS TIME, THE REAL PROBLEM OCCUR. THE ENGINE SOUNDS SO LOUD..IT'S HYBRID CAR SUPPOSED TO SO QUIET (THAT'S WHAT SOUNDS USUALLY). LATER ON, I FOUND OUT HOW TO STILL CAN DROVE IT, BUT WITH HIGH RISK SUDDENLY LOSE POWER ON THE STREET. LATER FOUND OUT, WHEN THE CAR IN MOTION, THE HYBRID SYSTEM DIDN'T WORKED COMPLETELY, AND THE TRANSMISSION SOUND VERY ROUGH. EVERY TIME WHEN COME TO BRAKE OR WANT TO SLOW DOWN, CAN FEELS OBVIOUSLY AND HEARD THE TRANSMISSION IS VERY ROUGH MAKING CLUTCH LOUD SOUNDS. THE CRUISE CONTROL SYSTEM ALSO TOTALLY NOT FUNCTION. WHEN IN STATIONARY, VERY FIRST WHEN STARTED THE ENGINE, MADE LOUD SOUNDS ON THE ENGINE, AND CAN'T REVERSED OR MOVE FORWARD, JUST STAYED IN PLACE. THE DASHBOARD DISPLAY "CHECK HYBRID SYSTEM". AND ON THE MIDDLE SCREEN DISPLAYING, "LOW VOLTAGE DC / DC CONVERTER".

NHTSA ID

11222226

Incident

Jun 22, 2019

Mileage

10 mi

ENGINE/TRANSMISSION BECOMES VERY SLUGGISH AS TEMPERATURES DROP AND THE TRANSMISSION SEEMS TO BE "ENGINE BRAKING" THE VEHICLE, MAKING COASTING NEARLY IMPOSSIBLE. PUTTING THE VEHICLE IN NEUTRAL ALLOWED THE CAR TO NORMALLY COAST BUT ONCE BACK IN DRIVE, ACCELERATION WAS TAXING. THE VEHICLE LACKS ANY POWER AND IS RUINING THE FUEL ECONOMY TRYING TO GET THE CAR UP TO SPEED.

NHTSA ID

11058078

Incident

Jan 2, 2018

Mileage

4,230 mi