In 2001, Kia launched their luxury vehicle, the Optima, to cap off their line-up. The 2007 model year -- fresh off a redesign in 2006 -- came standard with a 2.4-liter four-cylinder engine that produced 162 horsepower. The 2007 Optima had an optional 185-horsepower, 2.7-liter V-6 engine available. Both engines had a distributorless ignition system, and utilized small coil packs that sat on top of each spark plug. Kia recommends changing the spark plugs in the Optima every 100,000 miles.
Check the gap between the ground and center electrodes on the base of all four new Denso SK16PR-A11 (or equivalent) or six new NGK ILFR5B11 (or equivalent) spark plugs, using a spark plug gap tool. Kia recommends a gap between 0.039 and 0.043 inches. Exchange any spark plugs with and incorrect gaps for new ones, as the gap is non-adjustable.
Remove the plastic cover from the top of the engine by unscrewing the retaining nuts with a wrench and socket and pulling the cover off the engine.
Unplug the wiring harness on top of a coil pack by pressing the locking button and pulling the wiring harness away from the coil. Remove the coil pack retaining bolt, using a ratchet and socket, and pull the pack up to remove it from the spark plug.
Remove the spark plug from the engine, using a ratchet, 6-inch extension and a 16-mm spark plug socket.
Pull the old spark plug from the 16-mm spark plug socket and insert a new Denso SK16PR-A11 (or equivalent) spark plug, if fitted with a 2.4-liter engine, or an NGK ILFR5B11 (or equivalent) spark plug, if fitted with a 2.7-liter engine. Feel for the spark plug to "click" into place inside the spark plug socket.
Hand-tighten the spark plug into the engine, using the 16-mm spark plug socket and a 6-inch extension. Attach a torque wrench and apply 11 foot-pounds of torque to the spark plug.
Apply a thin coat of dielectric grease inside the rubber boot on the base of the coil pack and press the coil onto the spark plug until it "clicks" into place. Tighten the ignition coil packs to 4 to 5 foot-pounds, using a torque wrench and socket. Plug the wiring harness back into the top of the coil pack.
Repeat steps 3 through 7 until you replace all four spark plugs on the 2.4-liter engine, or all six plugs on the 2.7-liter engine.
Reinstall the plastic engine cover and tighten the retaining nuts to 3 to 4 foot-pounds, using a torque wrench and socket.
