2018 Kia Niro Engine Problems

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.

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.

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.

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.

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)

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.

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.

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

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.

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".

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.