How To Replace Spark Plug

By: Banks Jefferson

Break Studios Contributing Writer

Need to know how to replace a spark plug? Replacing spark plugs is part of the routine maintenance on a car. Learning how to replace spark plug is not as difficult as it sounds. When purchasing the spark plug, know the engine size and the number of spark plugs needed, usually six or eight. Plugs are generally sold in sets, but they can be purchased as singles.

To replace a spark plug you will need:

  • ratchet
  • ratchet extension
  • spark plug socket
  1. Battery cable. Disconnect the negative battery cable, this way every thing is off and getting shocked by the spark plug is out of the picture. Yes, the spark plug can give a nice little jolt.
  2. Setting the spark plug. Use a spark plug gap tool to set the spark plug to the correct setting. Check with the auto parts dealer or read the manufacturers guidelines for proper spark plug settings. Most of the plugs made today are already set, but it never hurts to be sure.
  3. Removing spark plug wires. Next pull the spark plug wire off the spark plug at the tip. Spark plug wires must be replaced in the same order they are removed. To be certain, replace one plug at a time.
  4. Cleaning debris. Blow as much debris out of the spark plug housing as possible. Dirt and oil will accumulate, and this needs to be removed to lessen the chance of cross threading.
  5. Removing the spark plug. Place the spark plug socket over the spark plug and twist it out, be careful to have a firm grip and do not break the spark plug. For a novice it is best to do one plug at a time, and replace the wires simultaneously. Usually the spark plugs in the back are the hardest to change.
  6. Placing the spark plug. Place the new plug carefully into the spark plug housing. Focus and feel the threads as you turn. If it seems the plug is cross threading as you replace the spark plug stop and start over. Do not cross thread the spark plug.
  7. Replacing spark plug wires. After replacing the plug make certain the spark plug wires are tightly snapped on, reconnect the battery and start the engine.

After the spark plugs have been changed make sure all tools are out of the engine. When putting on the spark plug wires make sure the metal cap on the wires snap back on the new spark plugs. Discard the old plugs.

Posted on: Jun. 12, 2010