Car · Kia problems

2018 Kia Optima problems

233 owner complaints filed with NHTSA for the 2018 Kia Optima. The most reported area is engine and engine cooling (62% of them). NHTSA also lists 80 service bulletins and 3 recall campaigns.

Counts are what owners told NHTSA, as filed. NHTSA does not confirm each report, and a complaint is not proof of a cause. Injuries: 9. Deaths: 0.

Complaints by area

Each bar is the share of this model year's 233 complaints that name that area. A complaint can name more than one area, so the shares add up to more than 100%.

• Engine and engine cooling144 · 62%
• Other or unknown38 · 16%
• Electrical system33 · 14%
• Power train (transmission and drive)19 · 8%
• Service brakes17 · 7%
• Exterior lighting14 · 6%
• Fuel system13 · 6%
• Steering12 · 5%

13 smaller areas not shown (44 complaints in total).

Do not compare models by these numbers. NHTSA has no sales count for each model, so a model with more complaints may just have sold more cars. Use them to see which areas owners write about, not to rank cars.

Service bulletins

NHTSA's database lists 80 repair bulletins from Kia for the 2018 Kia Optima. A bulletin is a repair instruction sent to dealers. It is not a recall and does not mean your car is covered. The 8 newest:

1. SC340_TSB_R5Received May 1, 2026

   Engine and engine cooling

   New/revised sections of this bulletin are indicated by a black bar in the margin area.

2. SC340Received December 2, 2025

   Voluntary emissions service campaign: theta II 2.4L GDI EMISSIONS ECM LOGIC IMPROVEMENT (SC340) - This bulletin provides information to upgrade the Electronic Control Module 'ECM' system software...

3. SC340_POCReceived October 24, 2025

   Electrical system

   Voluntary emissions service campaign: SC340_poc: proof of correction card.

4. SC340_QAReceived October 24, 2025

   Electrical system

   Voluntary emissions service campaign: question and answer (SC340) - This document is the Question and Answer Guide containing the most frequently asked questions regarding the Voluntary Emissions...

5. SC340_STKRReceived October 24, 2025

   Engine and engine cooling

   SC340_stkr: voluntary emissions service campaign completion label/sticker.

6. TSB_CLI057Received October 30, 2024

   Visibility and wipers

   Heating, ventilation, and air conditioning (HVAC) blower motor fuse relocation - This bulletin provides the procedure to relocate the Heating, Ventilation, and Air Conditioning (HVAC) blower motor...

7. TSB_TRA046_R4Received June 4, 2024

   Power train (transmission and drive)

   Information relating to the correct transmission fluid type and fill quantity requirement for each Kia model.

8. CS2310Received August 2, 2023

   Technical service bulletin customer satisfaction: Kia genuine remote start control module upgrade for anti-theft logic compatibility (CS2310) - this bulletin provides information to update the...

Recalls

NHTSA lists 3 recall campaigns for the 2018 Kia Optima. Recall repairs are free at a Kia dealer.

1. 21V844000October 29, 2021

   Engine

   The connecting rod bearings inside the engine may wear prematurely, which can result in engine damage.

2. 23V594000August 24, 2023

   Latches/locks/linkages

   The trunk latch base may crack, preventing the opening of the trunk from the inside.

3. 18V161000March 8, 2018

   Hybrid propulsion system

   These vehicles are equipped with a Voltage Protection Device (VPD), designed to protect the high voltage battery module, that may activate inadvertently.

See all 3 recalls for the 2018 Kia Optima, or check your VIN below to see which are open on your car.

Common repairs in this area (not a diagnosis)

These are repair jobs that sit in the areas owners report most. A complaint may need a diagnosis first: the same symptom can come from many causes, and a serious one such as engine failure is not fixed by a cheap part. They are not a forecast of what your Optima will need. Ranges are US estimates for all makes.

This model year has an engine recall in NHTSA's data. Before you pay for an engine repair, check the recalls and ask the dealer about warranty extensions for your VIN. Those repairs can be free.

Start with a diagnosis

• Diagnostic scan (check engine light)$55 to $250

Engine and engine cooling 144 complaints · 62%

No repair price here: this area usually needs a diagnosis first. A diagnostic scan (check engine light) runs $55 to $250.

Electrical system 33 complaints · 14%

• Battery replacement$150 to $470
• Alternator replacement$360 to $930
• Starter replacement$280 to $740
• Battery cable replacement$100 to $340

Power train (transmission and drive) 19 complaints · 8%

• Transmission fluid service$140 to $480
• Transmission solenoid replacement$290 to $1,200
• Torque converter replacement$880 to $2,475
• Clutch replacement (manual transmission)$1,000 to $2,050

Service brakes 17 complaints · 7%

• Brake pad replacement (front)$190 to $400
• Brake rotors and pads (front)$320 to $790
• Brake pad replacement (rear)$180 to $420
• Brake caliper replacement (one wheel)$240 to $590
• Brake fluid flush$75 to $180

Check a quote you got

Check your VIN

Complaints and bulletins cover a whole model year. Only the VIN shows what is open on your car.

By VIN By year, make and model

VIN (17 characters, on the dashboard by the windshield or the driver door jamb)

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Look up this VIN

Recall and complaint data comes from NHTSA, the US government's vehicle safety agency, and is cached for up to a day. Recall repairs at a dealer are free. A recall that is not listed may not apply to your car or may not be filed yet. Check nhtsa.gov/recalls too.

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2018 Kia Optima: questions

What are the most common problems on the 2018 Kia Optima?

Of the 233 owner complaints filed with NHTSA for the 2018 Kia Optima, 144 (62%) name engine and engine cooling, and 33 (14%) name electrical system. A complaint can list more than one area, so the shares add up to more than 100%. These are owner reports, not proven causes.

Is the 2018 Kia Optima reliable?

These numbers cannot say. NHTSA complaints have no sales count to compare against, so a high number on one model does not mean it fails more than another. Use them to see which areas owners write about, then check your own VIN for open recalls.

Do these complaints include crashes or fires?

Owners marked 10 of the 233 complaints as involving a crash and 10 as involving a fire. They also reported 9 injuries and 0 deaths. NHTSA records these as the owner reports them and does not confirm each one.

How many recalls does the 2018 Kia Optima have?

NHTSA lists 3 recall campaigns for the 2018 Kia Optima. Recall repairs are free at a Kia dealer. Enter your VIN to see which ones are open on your car.

What is a service bulletin?

A service bulletin is a repair instruction a maker sends to its dealers. It is not a recall, and it does not mean your car is covered. NHTSA lists 80 repair bulletins for the 2018 Kia Optima.

More

• 2019 Optima problems
• 2017 Optima problems
• 2016 Optima problems
• 2015 Optima problems
• 2014 Optima problems
• 2013 Optima problems
• 2012 Optima problems
• 2011 Optima problems
• 2018 recalls
• All Kia recalls
• Kia problems by model
• Check-engine codes

Sources

• NHTSA complaint and technical service bulletin files, checked October 29, 2026
• NHTSA recalls

Complaint, bulletin and recall counts come from NHTSA as filed. Repair prices are estimates from our own ranges. Not a repair shop, estimates only.