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 Clunking or clicking noise from the steering column due to a worn EPS flexible coupling. 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.
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Build the inspection planReliability snapshot
Based on the documented faults on this page for the Kia Optima.
4.7/ 10
- Critical
- 1
- High
- 1
- Medium
- 3
- Low
- 3
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.
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Build the inspection planElectricalLow
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.
SteeringMedium
Clunking or clicking noise from the steering column due to a worn EPS flexible coupling.
- Typically appears
- 50,000-70,000 miles
- What to inspect
- With the engine running and the vehicle stationary, rapidly rock the steering wheel left and right. Listen for a distinct plastic or metallic clunk from behind the dashboard.
BrakesMedium
Electronic Parking Brake (EPB) failing to release fully, leading to binding rear brake calipers.
- Typically appears
- 40,000-80,000 miles
- What to inspect
- Engage and disengage the EPB switch multiple times. Listen for groaning from the rear wheels and ensure the car rolls freely in neutral without rear-end drag.
ExteriorLow
LED Daytime Running Lights (DRL) flickering, dimming, or failing completely, requiring a costly headlight unit replacement.
- Typically appears
- 4-6 years
- What to inspect
- Turn on the ignition and headlights. Visually inspect both front DRL strips for any flickering, dim patches, or completely dead LED sections.
EngineMedium
Hesitation or stuttering under light acceleration caused by soot build-up in the EGR valve on 1.7 CRDi models.
- Typically appears
- 60,000-100,000 miles
- What to inspect
- Hold the engine revs steadily at 1,500-2,000 rpm whilst stationary. Feel for misfires or rough running, and check the instrument cluster for an illuminated EML.
Inspecting a Kia Optima?
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Build my inspection planFrequently 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.
Are there common issues with the Optima PHEV charging system?
The Plug-in Hybrid (PHEV) variant is generally reliable, but the onboard charger (OBC) can occasionally fail, preventing the high-voltage battery from accepting a charge. Dealers should always test the Type 2 charging cable on the forecourt to ensure the charging indicator illuminates and the dashboard confirms active charging.
Does the 1.7 CRDi engine use a timing belt or chain, and when does it need replacing?
The 1.7-litre CRDi diesel engine utilises a timing chain rather than a rubber belt. While designed to last the lifetime of the vehicle, poor servicing can lead to chain stretch or tensioner failure. Listen for a distinct metallic rattle from the engine bay during a cold start to identify wear.
What should I look out for on the 7-speed DCT automatic gearbox?
The 7-speed dual-clutch transmission, paired mostly with the 1.7 CRDi, can suffer from premature clutch pack wear. During a test drive, check for excessive juddering when pulling away from a standstill or hesitation when shifting between first and second gear. Routine fluid changes are critical to maintain clutch longevity.
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.
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