— Kia Sorento engine problems caused the National Highway Traffic Safety Administration to open an investigation into coolant loss, high engine temperatures and smoke flowing from the 3.3L Lambda II engine compartments.
The engine problems were occurring in 2016-2017 Kia Sorento SUVs, with drivers complaining about vehicles that lost motive power.
NHTSA opened the investigation into Kia Sorento engine problems in November 2023 and began by requesting data relating to the 3.3-liter Lambda II engines.
Safety regulators knew of complaints about the Sorento engine problems, but Kia responded to regulators in February 2024 by saying more than 2,000 complaints and other reports had been filed. In addition, more than 2,411 Lambda II engine warranty claims had been filed.
However, only 53 complaints alleged the Sorentos lost power. Kia told NHTSA the majority of the reports involved minor engine problems.
Once safety regulators erased duplicate reports, there have been 77 Sorentos that lost motive power due to engine problems, representing a report rate of 59 per 100,000 Sorento SUVs.
Data show the 2016 Kia Sorento has the highest complaint rate and loss of motive power report rate across the Sorentos and peer model populations.
There are no reports alleging the Sorento engine problems caused a crash or fire, but one consumer says they suffered a minor burn while removing the coolant reservoir cap following a loss of motive power incident.
Kia found if the threads of a head bolt hole in the engine becomes damaged, the clamping force between the cylinder head and engine block can decrease in the area of the head bolt.
Kia says a Sorento driver receives numerous warning signs before the SUV loses power.
"According to Kia, potential warning signs associated with this failure include coolant leak/consumption or noticeable coolant odor, engine oil leak/consumption, engine temperature gauge rising to “H” (hot), check engine light illuminating, engine cooling fan remaining on following the engine being shut off, HVAC system not functioning properly, unusual engine noise, difficulty starting the vehicle, and smoke/condensation emitting from the engine compartment or exhaust." — NHTSA
To mitigate the Sorento engine problems, in 2017 Kia increased the engagement depth of the head bolt threads for all the engines which lowered the incident rate to eight per 100,000 model year 2018-2020 Kia Sorento SUVs.
Kia also announced Sorento extended warranty campaign WTY035 in December 2023 titled, "2016-2017 KIA SORENTO VEHICLES EQUIPPED WITH 3.3L V6 ENGINES COOLANT LEAK."
The campaign extended the Sorento warranty from 5 years / 60,000 miles to 15 years / 180,000 miles, whichever comes first.
And extended warranty campaign WTY039 was launched in May 2024 for 2014-2015 Kia Sorento, 2015-2016 Kia Sedona and 2014-2017 Kia Cadenza vehicles equipped with the 3.3L engines.
NHTSA has closed the Kia Sorento investigation into engine problems based on Kia's actions.