EngineCritical
Theta II 2.0T/2.4L engine failure (bearing/knock) — recalls and warranty extensions apply.
- Typically appears
- 60,000+ miles
- What to inspect
- Listen for knock; confirm the knock-sensor recall and any engine replacement.
2016–2020 Kia Optima — common problems & known faults
The Optima is a well-equipped, stylish sedan, but it shares the Theta II engine family's failure risk — the priority check.
Compiled & reviewed by the VehicleFaults Research Team · last reviewed July 2026
Known faults to check
EngineHigh
Excessive oil consumption.
- Typically appears
- 70,000+ miles
- What to inspect
- Check oil level and history.
ElectricalLow
Infotainment and sensor glitches.
- Typically appears
- Any
- What to inspect
- Test the screen and features.
TransmissionLow
Occasional harsh shifts.
- Typically appears
- Any
- What to inspect
- Test-drive for smooth engagement.
Inspecting a Kia Optima?
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Generate a free checklistFrequently asked questions
Do Kia Optima engines fail?
The Theta II engines have a documented failure history with recalls — verify the knock-sensor update and any engine replacement.
Is the Optima a good used buy?
Strong value if recall history is confirmed and oil use is clean.
What's the knock-sensor recall?
A detection system added to catch bearing wear early — confirm it was installed.
Sources & further reading
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.