1.6L/2.5L turbo oil consumption and rare bearing issues.
- Typically appears
- 50,000+ miles
- What to inspect
- Check oil level and confirm any engine recall completion.

The K5 (formerly Optima) is a sharp midsize sedan. It's reliable but the turbo engines warrant a used-car check.
Compiled & reviewed by the VehicleFaults Research Team · last reviewed July 2026
The most commonly reported faults on the 2021–2024 Kia K5 are 1.6L/2.5L turbo oil consumption and rare bearing issues, 8-speed DCT on turbo can hesitate at low speed and Clunking or popping noise from the front end when turning or navigating speed bumps, caused by worn front strut top mounts. Most reported issues are medium or low severity, but a pre-purchase inspection is still recommended. Full inspection points, onset mileage and what to check are listed below.
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Build the inspection planBased on the documented faults on this page for the Kia K5.
Guidance only · reflects reported patterns, not a specific car's condition.
Which faults an average example has usually reached depends on its age. Pick a model year for the faults that matter on that build.
1.6L/2.5L turbo oil consumption and rare bearing issues.
8-speed DCT on turbo can hesitate at low speed.
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Build the inspection planInfotainment reboots and USB/charging faults.
Front pad wear on city cars.
Rattling or creaking noise from the panoramic sunroof over uneven surfaces due to dry tracks or degraded weatherstripping.
Clunking or popping noise from the front end when turning or navigating speed bumps, caused by worn front strut top mounts.
Excessive wind whistling from the A-pillar or front door glass at motorway speeds due to poor door seal fitment.
Rough idle, difficulty starting after refuelling, or an illuminated engine management light caused by a sticking EVAP purge control valve.
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Build my inspection planYes overall — check the turbo engine's oil use and the dual-clutch feel.
The DCT can hesitate; a careful test-drive will reveal it.
Engine oil use, DCT smoothness and infotainment.
The optional all-wheel-drive system on the 1.6L turbo models is generally robust, but the electro-hydraulic coupling can occasionally suffer from fluid degradation. Dealers should ensure the vehicle doesn't exhibit a binding sensation or tyre scrub during tight, low-speed turns, which indicates the coupling is failing to disengage properly.
Yes, these engines utilise a dual fuel injection system and a complex thermal management module instead of a traditional thermostat. It is crucial to use the exact specified grade of fully synthetic oil to prevent timing chain tensioner wear and to ensure the sophisticated cooling system functions correctly.
Early 2021 and 2022 models often suffer from aggressive calibration in the Advanced Driver Assistance Systems. The lane keep assist can forcefully tug the steering wheel on narrow roads. A dealer can resolve this by applying the latest manufacturer software updates to the forward-facing camera module via the diagnostic port.
Faults are compiled from documented recalls, technical bulletins, owner reports and mechanic sources, then reviewed for accuracy. This is guidance only · not a substitute for a professional inspection.
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