How to Guides

Changing Your Engines Spark Plugs

Wil Parker posted this on May 20, 2014

Changing Your Engines Spark Plugs

For each cylinder in your car, there is a small spark plug.  This is from where your air and fuel mixture gets the zap it needs to ignite.  A spark plug is nothing more than an energy conductor with a small gap.  This gap forces the electricity to jump from one side to the other, creating a small spark as it does.  That spark should be strong enough to set the gas vapors aflame and get your engine going.  

Why Do You Have to Change Spark Plugs?

Spark plugs are delicate little parts whose performance is hindered by a variety of circumstances.  Keeping them in good shape will improve your gas mileage and help keep your engine from misfiring.  Inefficient ignition at the chamber can lead to excessive emissions and poor car performance.  How often spark plugs need to be changed depends on a lot of factors such as the way you drive, the type of gas you put into your tank and even the overall condition of your engine.  

What Are The Symptoms of a Bad Spark Plug?

The most common problem with a spark plug that is not producing a spark is engine misfire.  A misfiring engine means that one of the chambers in the combustion order is not producing any energy causing the engine to buck or jerk as it is skipped over.  An engine misfire can get so severe that your car will stall when idling.  You are also wasting more gas when one or more of the spark plugs has gone bad.  Luckily replacing spark plugs yourself is easy and inexpensive.  Start by ordering a new set of high quality spark plugs from  They will make sure that you get the set that is meant for your car with the best performance rating.


Tools For the Job

  1. Ratchet Wrench
  2. 12 inch socket extension
  3. Spark Plug Socket 
  4. Work Gloves

Getting the Job Done

  1. There is a method behind the madness when changing your spark plugs.  Be sure to follow the directions in the precise order, or else you will create a big mess to have to sort out.
  2. Change all of the spark plugs while you are in there.  If one has gone bad the rest will soon follow suit.
  3. Find the spark plugs inside of your engine.  This can be done by following the path of the thick black wires inside the engine bay.  There should be one for each cylinder, so if you are driving V-6 look out for six spark plugs.  A four cylinder engine will only have four.  A V-8 will usually have two sets of four located on either side of the engine.
  4. This is when your method could lead to madness.  Resist the urge to pull all of the spark plugs out in one shot.  They fire in an exact order, so it is important that you don’t mess that up, which you will if you take them all out at once.  Changing them out one by one will ensure that you don’t.
  5. Start at the end and pull the wires off of the head of the first spark plug, grasping it as close to the engine as you can.
  6. Use your spark plug socket with the extension to remove the spark plug from its position. 
  7. Push the plug wire end of the plug all the way into the extension.
  8. Carefully put your new spark where the old one was.  Don’t bang it or you can mess up the gap.  Slowly screw it in by hand to avoid cross threading the plug.
  9. When it is as tight as your fingers can get it, finish the job with your spark plug socket and wrench.
  10. Don’t over tighten or you could damage the spark.  If you have a torque wrench, now is the time to use it and adjust the spark plug to your cars specs.
  11. Continue with the rest of the spark plugs one at a time until they all have been replaced.

Now you can go ahead and start your car to see how it sounds.  It should sound like you just rolled out of the new car lot.  If you chose to do things your way and take all the plugs out at once, your car probably won’t start.  Or you will hear a very loud bang.  Now you have to go back, find the right firing order, set the engine to dead center, match with the points, and start all over again.  You should have just listened the first time.

If you would rather see someone in action changing out spark plugs, check out our how to video and watch a pro get it right the first time.

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