Owners of other Kia and Hyundai vehicles such as the Optima, Forte, Cadenza, K900, Sorento, Sportage, Sedona, Soul, Elantra, Veloster, Sonata, Azera, Tucson, Santa Fe, Genesis and Equus may also find these DIY instructions to be helpful.

The OEM spark plugs in this 2014 Kia Rio are NGK Iridium part number SILZKR6B10E or SILZKR6B-10E.

A few other iridium spark plugs that should be compatible with their part numbers are as follows: Autolite XP6203 or XP5703, Hyundai 1884610060, Denso Iridium ZXU20HCR8 and Denso (3445) XU22HDR9.

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

Set the plastic engine cover aside in a safe place.

If you have access to compressed air or a wet/dry shop vacuum, thoroughly clean off the top of the engine to help prevent any debris from falling in to the cylinder when you remove a spark plug.

Then pry out the grey plastic locking tab on the electrical connector for the ignition coil. You may need a small flathead screwdriver in order to pull out the tab.

Loosen the bolt holding the ignition coil in place by turning it in the counterclockwise direction with the 10mm socket and ratcheting wrench.

Set the 10mm bolt aside in a safe place.

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

Carefully lower the socket over the old spark plug and then loosen it in the counterclockwise direction.

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 minutes or more 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 spark plug has been loosened, detach the ratcheting wrench and spin it out the rest of the way by hand.

If the rubber insert from the spark plug socket is attached to the old plug, pull it off and push it back in to the socket.

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 OEM spark plugs which are the NGK SILZKR6B10E iridium.

(An optional step is to apply some anti-seize grease to the threads on the spark plug. Most spark plug manufacturers recommend that you should not use anti-seize grease since it can lead to over tightening. Some mechanics believe that using anti-seize grease on the spark plugs will help prevent them from becoming stuck or "frozen" in to the cylinder head if they are not removed again for 100,000 miles.)

If you have a spark plug gap gauge, check that the new spark plugs are gapped to the manufacturer's specification listed on the box. They should be pre-set from the factory, so don't worry if you don't have a gap gauge.

Push the new spark plug in to the 5/8" socket. Your spark plug socket should have a rubber insert or a strong magnet to securely hold the plug in place.

Carefully lower the spark plug down in to the well and spin it in by hand in the clockwise direction with the extension bar until it makes contact with the cylinder head.

If you are re-installing the old spark plug, tighten it to just barely past hand tight.

Do not over tighten the spark plugs 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 which will permit a stable electrical connection between the electrode tip at the top of the spark plug and the ignition coil.

Lower the ignition coil down in to the spark plug well and rotate it back and forth a few times to help distribute the dielectric grease.

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

Push the power plug straight on to the ignition coil until it clicks securely in place.

Line up the friction fasteners on the bottom of the plastic engine cover with the metal pegs on the top of the engine.

Firmly push the engine cover in to place. Check that it is securely attached to the engine.

Start the engine and listen for any strange noises that may indicate a problem such as a loose spark plug or a loose electrical connector.

Be sure to record the spark plug change in your car's service records.

For more, check out my other 2012-2016 Kia Rio DIY Repair & Maintenance Guides.