Quick answer: Engine Air Filter Replacement on a 2016–2020 Kia Optima is rated Easy and takes about 10-20 minutes. No tools are required for this job, and parts cost about $20. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name |
Part Number |
Price |
Buy |
| Engine air filter |
— |
$20.00 |
|
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Step-by-Step Instructions
Follow these steps carefully
1
Prep and locate the air box
Park level, set the brake, engine off. Open the hood and find the large plastic airbox on the side of the engine, with a large hose running to the engine. The Optima's lid clips are oversized for the Theta II's high airflow — unclasp them outward to open, push the tabs UP until they click to close. If they don't click, the filter isn't seated.
🔧 Mechanic's note — Tom Becker
In my experience, If a clip won't click on reinstall, don't force it — pull the filter and reseat it. Nine times out of ten the filter shifted and is holding the lid up a millimeter.
2
Open the air filter housing
Unclasp the oversized clips on the lid — push the two tabs UPWARDS to lock them on reinstall; no tools required. Lift the lid only as far as needed, keeping it tethered if possible so it doesn't strain the intake tube. Note the lid orientation for reinstall.
3
Remove the old filter and clean
Lift the old filter out. The correct filter is: panel filter for Theta II 2.4L GDI / 2.0T (verify by engine). Hold the old element up to light — no light through the pleats means it was overdue. Wipe the airbox interior with a clean microfiber cloth, keeping debris away from the intake tube opening. The 2.0T turbo is harder on the filter than the 2.4L — check it more often with the turbo.
4
Install the new filter
Seat the new filter (panel filter for Theta II 2.4L GDI / 2.0T — verify by engine) with its rubber seal fully seated in the groove, pleats facing the same direction as the old filter. Run your finger around the entire perimeter — no gaps. An unseated filter lets dirt directly into the 2.4L/2.0T Theta II, causing premature engine wear.
5
Reseal and verify
Close the airbox lid evenly — press down uniformly so the seal compresses equally — and refasten every clip or screw. Double-check the intake tube clamps are snug. Start the engine and listen for 30 seconds: whistling or hissing means an air leak from an unsealed lid. Take a short test drive. Interval: every 15,000-30,000 miles.
All Done!
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
- • Installing the filter upside down or unseated so unfiltered air bypasses the element
- • Leaving debris in the housing that then gets sucked into the intake
- • Forcing clips/screws and cracking the plastic air box lid
- • Reusing a heavily clogged filter instead of replacing it
