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
Quick answer
The most commonly reported faults on the 2016–2020 Kia Optima are Theta II 2.0T/2.4L engine failure (bearing/knock) — recalls and warranty extensions apply, Excessive oil consumption and Infotainment and sensor glitches. Of the documented issues, 1 rated critical and 1 rated high · these are the ones worth inspecting first. Full inspection points, onset mileage and what to check are listed below.
Reliability snapshot
Based on the documented faults on this page for the Kia Optima.
6.5/ 10
- Critical
- 1
- High
- 1
- Medium
- 0
- Low
- 2
Guidance only · reflects reported patterns, not a specific car's condition.
Kia Optima problems by year
Which faults an average example has usually reached depends on its age. Pick a model year for the faults that matter on that build.
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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Check this exact carFrequently 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.