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After a few years of daily use, the battery inside the key fob remote control for the keyless entry system of your 4th generation (2016, 2017, 2018, 2019 & 2020) Kia Optima sedan can become weak or stop working entirely.

Check out my DIY tutorial for changing the battery (with the compatible replacement part number) by clicking on the text link above or the thumbnail image on the left.

If you need to change a burnt out map light bulb in the overhead console of your Kia Optima (or upgrade them both to brighter LED units), take a look at my DIY directions for the procedure (with the compatible replacement part numbers) by clicking on the text link above or the thumbnail picture on the left side of this paragraph.

If you need to change a burnt out vanity mirror light bulb located in the housing attached to the headliner above the sun visor in your Kia Optima, check out my DIY tutorial for the procedure (with the compatible replacement part number) by clicking on the text link or thumbnail image. You could also upgrade both the driver and passenger side bulbs to brighter LED units.

If you need to change a burnt out dome light bulb in the housing attached to the headliner above the rear passenger seats of your Optima (or upgrade it to a brighter LED bulb), check out my DIY steps for the procedure (with the compatible replacement part number) by clicking on the text link or thumbnail image.

If the air conditioning system in your fourth generation (2016, 2017, 2018, 2019 & 2020) Kia Optima sedan hasn't been working as well recently or the air coming out of the vents smell a bit musty or moldy, you probably need to clean or change the cabin air filter element in the HVAC blower motor housing. To view my DIY tutorial for the procedure (with the compatible replacement part numbers) click on the text link or thumbnail image.

If you need to change a burnt out license plate light bulb (or upgrade both lights to brighter LED bulbs) in the trunk lid of your Kia Optima, check out my DIY tutorial for the procedure (with the compatible replacement part number) by clicking on the text link above or the thumbnail image on the left.

If you'd like to upgrade the OEM door speakers in your Kia Optima, you'll first have to take off the plastic interior door panels.

To view my DIY directions for the procedure (with the compatible replacement speaker sizes), click on the text link above or the thumbnail image on the left.

The inner tail light housing on the trunk lid of a 4th generation (2016, 2017, 2018, 2019 & 2020) Kia Optima contains the reverse (or 'back-up') and the parking light.

Take a look at my DIY steps for the procedure (with the compatible replacement part numbers) by clicking on the text link or thumbnail image.

The main outer tail light housings on the rear corner of a Kia Optima contain the brake (or 'stop lamp'), rear turn signal (or 'indicator lamp') and the rear side marker light bulbs.

Check out my DIY tutorial for changing any of the light bulbs (with the compatible replacement part numbers) by clicking on the text link or thumbnail image.

If you'd like to manually move your Optima due to running out of gas, a dead 12V battery, in order to be towed, or some other mechanical issue, you'll need to release the shift lock mechanism to move the gear selector from 'Park' to 'Neutral'.

Check out my DIY instructions for the procedure by clicking on the text link or thumbnail.

If you need to change a burnt out cargo area light bulb in the trunk of your Kia Optima (or upgrade it to a brighter LED bulb), take a look at my DIY directions for the procedure (with the compatible replacement part number) by clicking on the text link above or the thumbnail image on the left.

If you've been having difficulty seeing out of the front windshield window of your Kia Optima when it is raining or snowing, you may need to change the wiper blades.

To view my DIY tutorial for the procedure (with the OEM blade sizes in inches and the compatible replacement part numbers), click on the text link or thumbnail image.

The best place to start when troubleshooting any electrical issue with your Kia Optima is to check for a blown fuse or a faulty relay in either the engine bay or the interior passenger compartment electrical panels.

Take a look at my DIY instructions for the procedure by clicking on the text link above or the thumbnail image on the left.

The engine air filter element for the Theta 2.4 liter GDI inline four cylinder motor should be cleaned at every oil change and replaced every 30,000 miles or at least every two years.

Check out my DIY directions for the procedure (with the compatible replacement part numbers) by clicking on the text link above or the thumbnail image on the left.

The headlight housings of a 4th generation (2016, 2017, 2018, 2019 & 2020) Kia Optima contain the low beam, high beam and front side marker light bulbs. To view my DIY guide for changing the bulbs (with the part numbers) click on the text link above or the thumbnail image on the left.

The front turn signal light bulbs in a fourth generation Optima are located down below the headlight housings in a separate light housing attached to the front bumper cover.

Some trim levels may also contain a fog light bulb in this lower housing.

If you've been having difficulty starting the engine in your Kia Optima on a cold morning and the OEM (original equipment manufacturer) 12 volt car battery is a few years old, you probably need to replace it.

Check out my DIY tutorial for the procedure (with the OEM battery's group size and the compatible replacement part numbers) by clicking on the text link or thumbnail image.

The iridium tipped OEM spark plugs in a fourth generation (2016, 2017, 2018, 2019 & 2020) Kia Optima can last up to 105,000 miles or 7 years but they should be checked and possibly changed before that mileage.

To view my DIY directions for the procedure (with the compatible replacement part numbers) by clicking on the text link above or the thumbnail image on the left.

Some of the symptoms of a clogged or failing PCV (positive crankcase ventilation) valve in your Optima's Theta II 2.4L GDI I4 engine include reduced performance, misfires at idle, increased fuel consumption and increased oil consumption or oil leaks.

Take a look at my DIY instructions for checking or changing the PCV valve (with the compatible replacement part numbers) by clicking on the text link or thumbnail image.

If you've been hearing a chirping, squealing or screeching sound coming from the engine bay of your Optima, you may need to change the OEM serpentine accessory belt on the Theta II 2.4 liter GDI inline four cylinder engine.

Check out the DIY instructions for changing the belt (also written instructions for changing the second small stretch belt) by clicking on the text link or thumbnail image.

The best way to keep your Optima running reliably for many years is to regularly change the motor oil and replace the oil filter on the Theta II 2.4 liter GDI inline four cylinder engine. The service interval specification in the owner's manual for an oil and filter change is every 7,500 miles (12,000 KM) or at least every year.

If you've been hearing a squealing, screeching or grinding noise coming from the front end of your Kia Optima when you step on the brake pedal, you probably need to change the front brake pads. To view my DIY tutorial for the procedure (with the compatible replacement part numbers), click on the text link above or the thumbnail image on the left.

If you've been hearing a grinding or squeaking noise coming from the back of your Optima when you step on the brake pedal, you probably need to replace the rear brake pads.

Check out my DIY tutorial for the procedure (including how to retract the EPB with an OBD2 scan tool) by clicking on the text link above or the thumbnail image on the left.

If you have an earlier 3rd generation (2011, 2012, 2013, 2014 & 2015) Kia Optima, check out my DIY repair and maintenance tutorials for your vehicle at the link below.

2011-2015 Kia Optima DIY Repair & Maintenance Guides

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