Skip the 2016 and the 2017. The 2020 is the quiet one, the 2023 the modern pick.

The engine the Sorento's reputation is built on, and nothing free stands behind it. The volume four-cylinder from 2016 through 2020: a 2.4-litre with GDI, meaning Gasoline Direct Injection, where fuel is sprayed straight into the cylinder. It belongs to the Theta II family shared with Hyundai, and its failure is the connecting-rod bearings — the metal shells the piston rods spin on — wearing early. It announces itself in a fixed order: oil consumption creeps up, a deep knock appears, then the engine seizes. Kia's answer is free software, the Knock Sensor Detection System, installed through Product Improvement Campaign PI1802 on 2015 model-year cars and, in Kia's own words, "all 2016-2018 MY Sorento vehicles equipped with 2.4L Gasoline Direct Injection ('GDI') and 2.0L Turbocharged GDI ('T-GDI') engines", and through PI1805 on "some 2019 MY Sorento vehicles". There is no such campaign for a 2020. When the system triggers it stores code P1326, and Kia's follow-up bulletins are titled engine replacement instructions for that code. Here is the part that decides the money: Kia's engine short-block warranty extension for the Sorento, WTY008, covers 2012 to 2014 model years and stops there. The software finds the problem. Nothing free pays for it, and an independent repair channel covering this generation puts a replacement engine at roughly $6,000 to $8,000.

Same family, same bearings, fewer cars. The turbocharged member of the same Theta II family, fitted to the upper trims of the third-generation car. Kia's own knock-sensor owner letter names it in the same sentence as the 2.4 — the software covers all 2016 to 2018 Sorentos with the 2.4-litre GDI and the 2.0-litre turbocharged GDI — so the connecting-rod-bearing story and the complete absence of any engine warranty extension apply to it identically. This row stops at 2018 rather than claiming later years because that owner letter is the last Kia Sorento document in our sources to name a 2.0-litre turbo by model year. The conditional fuel-pipe recall that follows an engine replacement, 18V907, reaches both engines: it covers 2012 to 2017 Sorentos that already received a replacement engine under warranty, under an earlier recall, or through the knock-sensor campaign, because the high-pressure fuel pipe "may have been damaged, misaligned or improperly torqued during the engine replacement procedure".

The one engine in this range Kia will actually replace for you. The 3.3-litre V6, and the reason a Sorento can be a bargain rather than a liability. Two Kia programmes cover it. Warranty Extension Program WTY035 applies to 2016 and 2017 Sorentos with the 3.3-litre GDI Lambda II built between October 2014 and April 2017: dealers are to "diagnose a coolant leak from the cylinder head gasket area and, if necessary, replace the engine sub-assembly", with coverage raised "from 5 years / 60,000 miles to 15 years / 180,000 miles". Warranty Extension Program WTY034 covers the high-pressure fuel pump on 2019 and 2020 V6 Sorentos, also to fifteen years and 180,000 miles. On top of that, recall 17V586 covers 2017 cars whose crankshaft "may have been improperly heat treated and may fail", again with engine sub-assembly replacement as the remedy. This engine is not faultless — owners report seizures with no warning and, on the 2019, high oil consumption followed by an oil leak at the back of the block — but it is the only Sorento engine in these eight years with real, free, long-term coverage behind it.

The redesign's base engine, and it has no bearing story at all. The naturally aspirated 2.5-litre in the lower trims of the fourth-generation car, and a genuinely different design from the Theta II despite the family name. Kia's own bulletin describes it precisely: "a naturally aspirated Theta III 2.5L GDI engine and dual fuel injection, where a low-pressure (MPI) injector and a high-pressure (GDI) injector independently supply fuel to each cylinder" — two injectors per cylinder rather than one. Its one documented fault in our sources is the direct-injection injector itself, which "may become damaged due to exposure to fuel containing ethanol, potentially resulting in the malfunction indicator lamp (MIL) illuminating, along with no-start, misfire, and/or reduced power, while driving at highway speeds"; Kia's campaign code for the replacement is CA2505 and it covers 2021 to 2023 models. Two independent reviews of this generation make the same practical point about it: it is much slower than the turbo, and it returns the same fuel economy, which is why most buyers end up in the turbo instead.

The engine most people want, attached to the gearbox most people complain about. The 281-horsepower 2.5-litre turbo, and in the fourth-generation Sorento it always comes with an eight-speed wet dual-clutch transmission — essentially two automated manual gearboxes sharing a housing, quick when pushed and awkward at walking pace. That combination is the loudest thing in the gen-four complaint file: hesitation from a standstill, lurching, RPM surging into the 5,000 to 6,000 range with no matching speed, and cars refusing to engage drive or reverse. Kia's own bulletin for 2021 to 2023 Sorentos with this engine and gearbox describes it in the same words owners use — "abnormal/harsh shifting, gear slipping, no gear engagement in Drive D and/or Reverse R shift selection" — and remedies it with improved electric oil pump control software. Recall 22V760 goes further on the 2021 and 2022 cars only: when the transmission oil pump malfunctions the fail-safe limp-home mode may be impaired, "which can result in a complete loss of drive power", and dealers "will inspect and replace the transmission, as necessary" free of charge. A published 40,000-mile long-term test of a 2021 hit exactly this and had the transmission replaced under warranty, a job that took 24 days. The engine adds two of its own items: recall 21V519 on the 2021, where "fuel may leak at the pipe connection between the high-pressure fuel pump and fuel rail", and recall 22V202 on the 2022, where "the oil supply pipe to the turbocharger may crack" and leak oil into the engine bay.

The version that stops accelerating on the freeway and cannot be reproduced at the dealer. The hybrid and plug-in hybrid share a 1.6-litre turbocharged petrol engine — Kia names it the Gamma 1.6L T-GDI in its own bulletins for the Sorento HEV and PHEV. Its complaint file is dominated by one repeating event: the message "Check Hybrid System — stop safely", the battery depleting, and the car losing the ability to accelerate, at 70 mph on freeways, at junctions and from a standstill. Dealers routinely cannot reproduce it and no code is stored. There is no recall for it. Three Kia documents sit around the edges of the problem and are all worth asking about by name: service action SA515 flushes the inverter coolant on 2021 to 2022 hybrids showing a "Refill inverter coolant" message, campaign SC325 inspects and replaces the auxiliary electric water pump on 2022 to 2023 hybrids for "coolant intrusion and/or corrosion", and a software bulletin covers 2021 to 2023 hybrids where "the engine oil becom[es] diluted with fuel and/or moisture caused by repeated short drive trips" in freezing weather. The plug-in adds a documented transaxle failure of its own: Kia's bulletin for 2022 to 2024 all-wheel-drive plug-in hybrids instructs dealers to "replace the transaxle assembly" on cars storing code P0C4E00 with a rough transition between electric and hybrid drive. Recall 22V447 also applies to the hybrid, for seat-belt pretensioners that may explode on deployment.