2018 Kia Optima Engine Problems

NHTSA component category: ENGINE · data through 07/12/2026

129Engine complaints

56.6%Of all 228 complaints

#1Most-reported category

Source: U.S. NHTSA complaint data. Complaints are unverified reports from vehicle owners — a complaint is not a confirmed defect.

How engine ranks on this vehicle

ENGINE129 · 56.6%

Unspecified / other37 · 16.2%

ELECTRICAL SYSTEM31 · 13.6%

POWER TRAIN18 · 7.9%

SERVICE BRAKES17 · 7.5%

Share of the 228 complaints citing each category; one complaint can cite several. Full breakdown on the 2018 Kia Optima overview page.

What owners report

“-Knock Sensor Detection System - ECU Logic Improvement - I Was driving with my infant son in the backseat. I was going 70 mph when…”NHTSA complaint 11524617 — filed 05/31/2023

“Car smoking white , and driving slow after I hit a pothole when it was raining hard.”NHTSA complaint 11524344 — filed 05/29/2023

“The contact owns a 2018 Kia Optima. The contact stated that the vehicle was sputtering while being started. The contact stated that the vehicle also…”NHTSA complaint 11522447 — filed 05/17/2023

Excerpts are shortened and scrubbed of personal details; they are individual, unverified reports.

Engine complaints by year filed

Frequently asked questions

Does the 2018 Kia Optima have engine problems?

Engine is the most-reported problem area on the 2018 Kia Optima: 129 of 228 complaints on file (56.6%). Complaints are unverified owner reports, not confirmed defects.

How many complaints does the 2018 Kia Optima have in total?

228 complaints were on file with NHTSA as of 07/12/2026. Across all categories, 9 involved a crash, 10 involved a fire, 8 reported injuries, and none reported deaths.

What does NHTSA's engine category include?

NHTSA assigns each complaint to standard component categories; this page reports the ENGINE category exactly as NHTSA defines and records it.

About this data — Complaint figures on this page are consumer reports submitted to the National Highway Traffic Safety Administration (NHTSA), a U.S. government agency. NHTSA does not verify individual complaints; a complaint is not proof that a defect exists, and counts reflect what owners chose to report, not confirmed failure rates. Recall information comes from official NHTSA safety recall campaigns; recall repairs are free at authorized dealers. Always check your specific vehicle by VIN at nhtsa.gov/recalls. CarModelProblems.com is an independent site and is not affiliated with NHTSA or any vehicle manufacturer. Data through 07/12/2026.