How to Change the Spark Plugs in Hyundai Cars

by Contributing Writer

The Hyundai car is a Korean built, mid-sized sedan with European styling. The engine compartment is located at the front of the vehicle, under the hood. Engine access is needed to complete this procedure. You can perform the spark plug replacement procedure with common tools and little to no experience. Refer to the Hyundai car service manual for the factory recommended parts and parts numbers needed.

Under The Hood:

 How to Change the Spark Plugs in a Hyundai XG350

Open the hood and locate the spark plug wires on the Hyundai XG350. The wires run across the top of the engine and are either blue or black (depending on the manufacturer of the last spark plug wires that were installed). The spark plugs are underneath the wires, so these must be removed. However, only remove them one at a time, starting with the right-most spark plug.

Pull the spark plug wire out. Hold onto the plug section of the spark plug wire and pull it out of the engine. There is nothing holding it in place, but it does fit snug over the top of the spark plug so you will need to pull pretty hard.

Attach the socket extension to the socket wrench and then attach the spark plug extension over the end of the socket extension.

Slide the socket wrench and extension down into the top of the engine and orient the wrench so that the socket extension slides over the top of the spark plug.

Turn the spark plug counterclockwise and pull the extension straight out fo the engine to remove the plug.

Hold the new spark plug in your hand so that you can easily see the electrodes. Slide the spark plug gap checker between the electrodes. The gap checker looks like a flat metal disc of varying thicknesses. On the face of the disc, there are numbers that represent different inches or millimeters of thickness. Adjust the gap between the electrodes by bending the top electrode on the plug either up with the assistance of the gap tool or down with your thumb until the gap is 0.043 in or 1.1mm. This gap measurement is specific to the XG350, so the gap must be made to this specification for optimum spark.

Insert the spark plug into the spark plug socket with the electrodes facing out and insert the plug into the engine. Turn clockwise to tighten the plug until you feel resistance. Then, give the plug an additional 1/8 to 1/4 turn.

Slide the spark plug wire back over the top of the spark plug and repeat steps 4 through 7 for each engine cylinder spark plug.

Items you will need

  • Socket wrench

  • Spark plug socket extension

  • Socket extension

  • Spark plug gap checker

 How to Replace Spark Plugs in a Hyundai Santa Fe

Turn off the engine and allow it to sit and cool for at least 30 minutes.

Locate the spark plug cables. Most Hyundai Santa Fe engines' cables are on the right and left sides of the engine about a quarter of the way down. Some of the engines' cables run along the front and back of the engine instead.

Remove and clean the boot or the cable. Grab the spark plug cable by the boot, turn it and then pull back on the wire to remove it from the spark plug. Lightly brush or blow out the boot.

Apply a light coat of anti-seize compound to the threads of the new spark plug and the cable boot. Anti-seize compound allows easy removal of the spark plug and boot the next time access is needed.

Thread the new spark plug into the cylinder well. Do not apply force to the spark plug as it is threading.

Tighten or loosen the spark plug to adjust its torque. The tension tester tool shows you the exact torque the spark plug requires. The torque varies depending on the spark plug's manufacturer. Read the package the spark plug came in to determine the proper torque for the spark plug.

Reconnect the spark plug cable and continue the process with the remaining spark plugs.

Items you will need

  • Spark plug socket

  • Socket wrench and extension

  • Anti-seize compound

  • New spark plugs

  • Tension tester tool

 How to Replace Spark Plugs on a 2005 Hyundai Sonata

2005 Hyundai Sonata Spark Plug Replacement

Remove the engine cover located on top of the engine.

Wipe around the base of each spark plug with a clean cloth to remove any debris.

Remove the ignition cover by twisting counter clockwise with a flat-head screwdriver. The ignition cover is located on the top of each spark plug ignition coil.

Press in the ignition connector key located on the right side of the wiring harness. Pull the connector away from the ignition coil.

Locate the mounting bolt on top of the ignition coil. Using a socket and wrench, turn the bolt counter-clockwise until it is removed. Pull straight up on the ignition coil to reveal the spark plug.

Turn the spark plug counter-clockwise, being careful not to damage the ceramic insulator on the spark plug. You can perform this task by using a socket wrench specifically designed for spark plug installation and removal.

Place the spark plug installation socket over the new spark plug. Insert into the top of the engine cylinder. Turn clockwise with the socket wrench until spark plug is tightened.

Replace the ignition coil and bolt.

Press the wiring harness back on.

Replace the ignition cover.

Replace the engine cover.

Items you will need

  • A clean, dry rag

  • Flat-head screwdriver

  • Spark-plug Socket

  • Socket wrench

 How to Replace Spark Plugs in a Hyundai Sonata

Turn off the Sonata engine and allow it to cool. This normally takes about 30 minutes.

Raise the hood and locate the spark plug cables along the side of the engine. Spark plug cables are normally 1/4 to 1/2 inch thick and plug directly into the engine.

Grasp the cable by its boot. This is the thicker piece that covers the spark plug or spark plug well. Turn the cable back and forth until the lock releases. Pull back on the cable to remove it. Complete the replacement process for each plug before moving on to the next.

Slide the socket, extension and wrench over the spark plug. Turn the wrench to the left to unscrew and remove the plug from the engine. Spark plug sockets have a cushion inside that grab the end of the plug to hold it in place.

Clean the well and boot with the wire brush. Do not rub hard on the well or boot or it will cause damage. Spray silicon in the boot and on the spark plug threads, so you can easily remove the spark plug the next time.

Insert the socket into the well and gently thread it into the engine. Test the tension with the tester. The tension a spark plug needs varies by plug manufacturer. Check the package to find the correct tension. If you need more tension, tighten the spark plug. For less, loosen or unscrew the plug.

Place the cable back onto the spark plug.

Repeat Steps 2 through 7 for the other plugs. Work your way down one side of the engine and then down the other as you replace or clean the spark plugs.

Items you will need

  • 16mm spark plug socket

  • Socket wrench with extension

  • Wire brush

  • Silicon spray

  • New spark plug

  • Tension tester