2021 Kia K5 Reliability Report

Sudden loss of drive power is the main pattern. The transmission fails without warning and the car coasts to a stop on the highway. Some units are replaced, one car twice before 16,600 miles. Other owners describe slipping, delayed or rough shifts, grinding between gears, and an engine that stays revved after they lift off the gas. One new car needed a transmission within 5 days because of a fluid leak. A few complaints filed here actually concern fuel tank recall delays, a failed brake vacuum pump, and coolant odor.

Power loss and major internal damage tend to show up at higher mileage. Reports include turbo-related power loss, coolant passing through the turbo into the head gasket, a failed thermostat with overheating, and a ruined motor after the oil drain plug fell out. Second owners learn the 10-year, 100,000-mile powertrain warranty does not transfer. Some cars shut off repeatedly on the highway and drop into limp mode. Other complaints describe strong coolant vapor escaping near the reservoir cap and a car that powers on its dash but will not start.

Fuel tank swelling deforms the rear floor and frame, sometimes badly enough that repairs cost more than the car is worth. Service campaign SC288 addresses the tank pressure problem. The other recurring issue is engine and underbody covers that break loose and drag or flap at speed, in one case damaging the fender and fog light housing. Owners also report a low front bumper that scrapes and pops off, a sunroof that shattered while driving, lifting trim under the rear window, and wind noise from the rear doors.

Airbags fail to deploy in serious crashes. Reports describe frontal impacts at 30 to 35 mph, a rear-end collision near 50 mph, and a deer strike at 65 to 70 mph, all with no deployment. Five reports involve crashes, five injuries are recorded, and one driver later died from her injuries. A rear seatback also unlatched in one frontal crash. Recall 23V149000 covers the airbags, though at least one owner waited on parts that were unavailable. Some complaints here instead concern fuel tank expansion under SC288.

Power steering cuts out without warning. The wheel stiffens or locks, a long list of driver-assist warning lights appears, and restarting the car sometimes clears it. Dealers often cannot find a cause, and one case began around 16,000 miles. Some cars lock the wheel right at startup, and in one case it later happened on the highway. A separate pattern is a hard pull to the right that alignments and new tires do not fix. Warped brake rotors that shake the wheel under braking also come up repeatedly.

The fuel tank expands while the car is moving. A loud explosion from the rear lifts the back seat, fuel leaks or squirts from the filler neck, and the gauge swings between full and empty. One report involves an injured back-seat passenger, and another occurred around 116,000 miles. Dealers sometimes find no cause, and one recall repair under 25V794000 stalled because parts were unavailable. Fuel odor in the cabin and a range display that drops far faster than the car is driven are also reported.

Driver-assist features work intermittently, switching on and off without explanation. In one crash, the steering wheel shuddered and went rigid during a slow turn. The driver lost control and hit a dumpster, and the airbags did not deploy. The dealer said the car could not be repaired under a federal recall campaign. Only 2 complaints are filed here, but the steering behavior matches the power steering failures reported under steering, so the two problems are worth checking together.