2015 Kia Optima · symptom sheet
Engine knocking or ticking
- 118owner reports
- 97,000median miles
- $6,000median quote
- 1involved a crash
Newest report Sep 20, 2026 · checked Oct 2, 2026
118 of the 319 reports of engine failure on the 2015 Optima describe engine knock.
Part of Engine failure, knocking or rod bearing (319 reports) · also: engine seized, rod bearing failure
Tick what matches of 118 reports
Engine knock on other Optima years
Report counts are for each model year on its own, so a newer car has had less time to collect them. Model years with too few reports of it for a sheet: 2018, 2019, 2020.
What got replaced
Owners who name the part that was replaced mention the knock sensor (33 reports), the rod bearing (11 reports) and the engine (9 reports).
Recalls and investigations
No recall on the engine covers the 2015 model year as of Oct 2, 2026.
NHTSA investigations into the engine on the Optima
Loss of motive power. Closed dec 12, 2023.
Engine fires. Closed feb 5, 2024, led to recall 23V-877.
Scope and timeliness. Closed dec 22, 2021, led to recall 17V-224.
What owners paid
9 of the 118 reports quote a price. Each dot is one quote. The middle half runs $3,000 to $7,200.
When it happens
The middle half of failures fell between 70,000 and 122,000 miles, from the 75 reports that gave a mileage.
Is this a known problem?
The manufacturer has sent NHTSA 17 service bulletins or notices for the 2015 Kia Optima that deal with this problem. Newest first.
Federal rules make a manufacturer send NHTSA a copy of any notice about a defect that goes to more than one dealer or owner. Most of these are service bulletins, the repair instructions manufacturers send to dealers. NHTSA generally leaves safety recall bulletins out of this file, and recalls are listed separately.
PRODUCT IMPROVEMENT CAMPAIGN: ENGINE REPLACEMENT INSTRUCTIONS FOR DTC P1326 (PI1802Y/Z) This bulletin provides information related to the Technical Service Bulletin previously published PI1802 titled "Knock Sensor Detection System - ECU Logic Improvement"; equipped w/THETA II engine.
ENGINE REPLACEMENT INSTRUCTIONS FOR DTC P1326 (PI1802Y/Z) This bulletin provides information related to the Technical Service Bulletin previously published PI1802 titled "Knock Sensor Detection System - ECU Logic Improvement" equipped w/THETA II engine.
PRODUCT IMPROVEMENT TSB_PI1802_R2 - Knock Sensor Detection System - ECU Logic Improvement - This bulletin provides information related to a software update to the Engine Control Unit (ECU) to install the Knock Sensor Detection System (KSDS) in order to protect the engine from ...
PRODUCT IMPROVEMENT CAMPAIGN ENGINE REPLACEMENT INSTRUCTIONS FOR DTC P1326 (PI1802Y/Z_Rev3) - - This bulletin provides information related to the Technical Service Bulletin previously published in July 2018 (PI1802 Rev 10, 03/16/2020) titled "Knock Sensor Detection System - ECU Logic ...
13 more on the 2015 Kia Optima page.
What owners wrote
“P1326 code flashing engine light knock sensor went out 3 times in 6 months and just replaced it again and this time engine light didn't go off I was reading that there was a recall on this but apparently mine doesn't state it. Car cannot pass emissions if engine light is on and the 15th of June is approaching. The car doesn't make any sounds or nothing.”
Filed Jun 8, 2026
“Car started making a horrible knocking.. Had a rod bearing failure. Engine was completely bad. And Kia refuses to fix and or reimburse me.”
Filed May 4, 2023
“Knock sensor replaced due to engine knocking did not fix the problem the cars engine does not work it julks and pulls really hard engine noise check engine flashing left me stalled on the main highway with my 2 children with no warning the car has engine oil to adequate levels maintenance was up to date”
Filed Mar 28, 2023
“Knocking noise coming from engine. Pulley is wobbly. Oil leak coming from timing cover. Knocking noise come from Connecting rod knocking. Engine will have to be replaced or rebuilt.”
Filed Feb 23, 2023
Should you keep driving it?
This page can't tell you that. 1 of 118 reports involved a crash and 1 people were hurt. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.
File your own report with NHTSA. Complaint counts are how a problem gets an investigation. How reports land on this sheet.
Guide Taking it to a shop? How to describe this problem so it gets found
Other problems on this car
- Engine stalls or loses power while driving 256 reports
- Check engine light or misfire 108 reports
- Brakes grind, pulse or wear early 89 reports
- Vehicle fire 70 reports
- Paint peels or body rusts 56 reports
- Engine rattles or ticks 49 reports
- Burns oil or oil level rises 37 reports
- Battery dies or the car will not start 30 reports
- Airbag warning light or recall 26 reports