Owners of other Kia or Hyundai vehicles such as the Optima, Cadenza, K900, Sorento, Sportage, Sedona, Soul, Elantra, Veloster, Sonata, Azera, Tucson, Santa Fe, Genesis, Cerato, Spectra, Accent, Sephia, i20, i30, ix35, i40 and Equus may also find these DIY instructions to be helpful.

The tools needed to complete this procedure include a 10mm socket with a 1/4" drive ratchet, a 5/8" spark plug socket, a 6" extension bar, a 3/8" drive ratcheting wrench and a tube of dielectric grease.

A few compatible replacement spark plugs with their part numbers include the following: NGK (4469) LFR5AIX-11, Bosch 9622, Autolite XP5325, Champion REC12WMPB5 (9055), Denso FK16HQR11 and ACDelco 41-835.

Set the engine cover aside in a safe place.

If you access to compressed air or a wet/dry shop vacuum, thoroughly clean off the top of the engine to help prevent from having debris fall down in to the cylinder well.

I'd recommend only checking or changing one spark plug at a time to further reduce the risk of having debris fall down in to the engine.

Slide the grey plastic locking tab back to unlock the electrical connector on the ignition coil.

Loosen the single bolt that holds the ignition coil in place by turning it counterclockwise with the 10mm socket and 1/4" drive ratcheting wrench.

Rotate the ignition coil back and forth to make sure that the rubber dust boot is not stuck to the top of the old spark plug.

Lift the ignition coil out of the spark plug well and set it aside in a safe place.

Carefully loosen the old spark by rotating it counterclockwise.

Try to avoid using excessive force to loosen the old spark plug to prevent from cracking the ceramic portion of the plug.

If you have trouble loosening the old spark plug, spray a small amount of penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait at least 15-30 minutes before attempting to loosen it again. If you don't have any penetrating oil, try spraying some WD-40 or warm up the engine for a few minutes to help expand the metal engine block.

Once the old spark plug is loose, detach the ratcheting wrench and spin it out the rest of the way by hand.

Inspect the old spark plug.

If the electrode end of the old spark plug looks ashy white, the plugs may have been exposed to high temperatures such as overheating or they may be the incorrect heat range for your driving conditions or environment.

On the other hand, if the old spark plug is grey or covered in dark black soot, the engine may be burning oil and should be examined by a professional mechanic.

I recommend buying the NGK (4469) LFR5AIX-11 iridium spark plugs since they have excellent reviews on Amazon.

Push the new plug in to the socket and lower it down in to the well.

Your spark plug socket should have a rubber insert or a strong magnet to hold it securely in place.

Spin in the new spark plug by hand in the clockwise direction until it makes contact with the cylinder head.

Attach the 3/8" drive ratcheting wrench to the extension bar and continue tightening the new spark plug in the clockwise direction.

If you are re-installing the old spark plug, tighten it to just a very small fraction of a turn past hand tight.

If you are installing a brand new spark plug, tighten it to just past the point when you feel the new crush washer collapse.

Do not over tighten the spark plug to prevent from cracking the ceramic body or stripping the aluminum threads.

Double check that the new spark plug is tight before moving on to the next steps.

The dielectric grease will help keep out any moisture or debris.

Replace the 10mm bolt and tighten it in the clockwise direction to secure the ignition coil in place.

Try to avoid over tightening the 10mm bolt to prevent from cracking the plastic ignition coil housing.

Push the electrical connector back in to place on the ignition coil.

Line up the plastic engine cover and push it back down in to place.

Start the engine and listen for any strange sounds that may indicate a problem such as a faulty wire, disconnected power plug or a loose spark plug.

For more, check out my other 2010-2013 Kia Forte DIY Repair & Maintenance Guides.