There are 11 owner-reported engine complaints for the 2021 Kia K5in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
The contact owns a 2021 Kia K5. The contact stated that the check engine warning light remained illuminated with DTC: P0471 displayed. The vehicle was included in NHTSA Campaign Number: 25V794000 (Fuel System, Gasoline) and was taken to the dealer for the recall repair where the dealer replaced the check valve. After receiving the recall repair, the check engine warning light remained illuminated with DTC: P0471 displayed. The vehicle was returned to the dealer, who diagnosed that the Exhaust Pressure Sensor was causing the Exhaust Gas Recirculation (EGR) Sensor to fail and needed to be replaced. The vehicle had not been repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 52,000.
I originally got my car 2023 from Carmax I took it in to Kia dealership to get my recalls done they kept my car for over 6 days without fixing it when I arrived I was showed a photo saying it’s after market parts on this vehicle and we can’t touch it also they stated my vehicle was dangerous to drive so I asked for documentation that my vehicle was denied and they refused also I called Kia cooperate to file a complaint to get proper documentation that my vehicle was denied they told me it was denied as well and said they can’t give me paperwork to state anything
no power at all all most in a accident with it when it lost power they said it’s the turbo l paid 33,000 for this car it had 35000 miles on it has 103000 on it when it lost power
The contact owns a 2021 Kia K5. The contact stated that while driving approximately 45 MPH, the vehicle jolted forward three times and then lost power. The contact stated that while driving at approximately 60 MPH, the check engine warning light illuminated. The contact steered the vehicle into an independent mechanic and the vehicle was inspected, and there was oil all over the engine compartment. The vehicle was taken to a dealer, where it was diagnosed, and determined that an unknown sensor was inoperable and needed to be replaced. The vehicle was repaired, but the failure recurred the same day the vehicle was retrieved. The vehicle was taken to the same dealer where it was diagnosed, and determined that the valve cover needed to be replaced. The vehicle was repaired, but the failure reoccurred nine times, and the valve cover was replaced each time. The manufacturer was notified of the failure. The failure mileage was approximately 45,000.
On [XXX] I took my automobile, a 2021 Kia K5 to Planet KIA of Charlotte NC located at 4700 E independence Blvd. I took it there to check what caused my engine light to activate. The initial diagnosis was a bad Sensor-Differential Pressure. Planet KIA repaired the Sensor-Differential Pressure at the cost of $501.17. My extended warranty company Route 66 covered $350.28 while I covered the remaining balance of $150.89. The engine light came on again the next day and while driving back to the dealership, I experienced the car slowing down and difficult to gain speed in highway traffic. I returned the automobile to Planet Kia of Charlotte and on [XXX}, I was informed that I had a valve failure which in turn caused my gas tank to swell. On [XXX] the warranty company denied request to pay for repairs due to their policy of not covering emissions which pertained to the valve. Kia refused to fix this problem due to a service campaign recall had been performed on the vehicle before I bought it. They found no issues with the vehicle pertaining to the valve or gas tank swelling. This is clearly a manufacturer’s defect, and it should have been repaired by the manufacturer. If you can, please help. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
On Mon, Nov 18, 2025, I was driving at 60 mph with cruise on. Suddenly cruise was cancelled and check engine and low oil pressure lights came on. I pulled off road at earliest point possible. Seemed to be running ok. Drove slowly to a convenience store and turned off engine. I checked oil and it was low. When I was walking out to car after buying some oil, I saw oil under car. I called tow service and had it delivered to dealership. Upon inspection, the dealership determined the oil drain plug had fallen out and the engine needs to be replaced. The oil had been changed by an independent shop at 75085 miles. This incident happened at 78,887 miles. I feel the drain plug would have fallen out before 3002 miles if it was put in loose. This issue needs to be made into a recall with reimbursements for engine replacements and towing. If this had happened on a busy road and engine seized, there could have been a wreck trying to get off road.
When you get in the vehicle to turn it on the lights are on an everything else accept for the engine. The dashboard says the the vehicle is on, however it is not. Diagnostics shows no problems. This is on going in the New K5 community.
Bought the car used and had it in within first two weeks with 6k miles on it for warped brakes. They repaired. Now it has 68k miles on it and had all maintenance. 2nd owner and now we are told the antifreeze is going thru the turbo and into head gasket and Kia will not do anything. We were not aware the 10 yr 100,000 miles was not transferable. 6k miles out of warranty and they want us to buy a motor. This car has always been maintained and should not need a motor with only 68k miles. The optima’s had the same issue as we also have an optima which was covered due to recall. This should be looked at. The dealership charged us 200 for diagnostics and said too bad you pay for it.
Car thermostat failure, car overheats and only 89000 miles
Vehicle engine shut off while driving down the highway. Traveling on 74 and while still in drive the engine abruptly shut off. Vehicle was started again and then it again shut off a couple miles down the road. When the vehicle was started a 3rd time it immediately went into limp mode. I was stuck on the side of the highway with vehicles going 70MPH around me. On my way to the dealership the car shut off multiple times potentially killing me multiple times. After 60 days at the dealership they said they fixed the problem. I drove the car 4 miles and it shut off on me on the highway again. I had a car almost crash into me along with trying to start the car and get off to a safe location. I still do not know what is going wrong with the vehicle but this could of killed me and others..... this needs to be addressed along with the fact they gave me the vehicle back just for it to do it again.
WHILE DRIVING THE VEHICLE AND AFTER IT IS PARKED AND ENGINE IS TURNED OFF THE COOLING SYSTEM ( COOLANT RESERVOIR ON UPPER RIGHT SIDE OF ENGINE ARE) ALLOWS ANTIFREEZE VAPORS AND HIGH PRESSURE TO ESCAPE INTO ENGINE AREA. WHEN PARKING IN A GARAGE THERE IS A VERY STRONG SMELL OF COOLANT. DEALER HAS VERIFIED THAT THE RADIATOR CAP APPEARS TO ACT AS A VENT ALLOWING VAPORS TO ESCAPE THE SYSTEM.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026