How to Replace Spark Plugs and Spark Plug Wires

An engine requires three things to run: fuel, spark, and compression. If any one of these components is missing from the magical formula, the engine will not run. However, if one of these three critical components is not performing up to par, the engine will run inefficiently and burn more gasoline than is necessary. But why do we change spark plugs and wires? They wear over time like many components on the vehicle. Voltage in the thousands flows through the spark plug so wearing down the electrode. Additionally, the plugs is subjected to high temperature and pressure, causing it to wear over time. The plugs and plug wires are two things that can be changed easily and will give your motor the kick it used to have.

To replace the plugs and wires, follow the steps below below. Some vehicles do not have wires, but rather, a coil on plug (COP) system. In this case, all that is replaced are the plugs.

  1. Remove any engine covers obstructioning access to the spark plugs and wires.
  2. Remove one wire at a time so as to not mix the wires. Removing the wires may prove difficult but despair not. There is a special tool that can be purchased from auto supply stores specifically for removing spark plug wires. Forty-five degree needle nose pliers can also be implemented to remove the wires. Simply hold on to the wire with the needle nose pliers and pry up against the valve cover. This will easily remove the wire.
  3. Next, take out the spark plug wire and set it off to the side.
  4. Now it's time to replace the spark plug. If you do not have a spark plug socket, purchase one. Your vehicle will either use a 5/8 "or 13/16" socket; it's a wise investment to have both.
  5. Attach your spark plug socket to a long extension and 3/8 "ratchet. Place the socket over the spark plug and begin loosing the spark plug in a counter-clockwise direction.
  6. We can now put in the new spark plugs. But before we do so we need to ensure that our new ones are gapped correctly. Most plugs made today are "pre-gapped", meaning that we do not have to make any adjustments to them. Ask the person at the auto-parts store what the correct gap is and purchase a "gapper" that will allow you to check the gap and make any adjustments.
  7. Place the gapper in the gap and see what it reads. This will typically be .038 to .044 ". If the gap is too small, place the gapper in the gap and enlarge it.
  8. Now install the new spark plugs by attaching a 5/8 "or 13/16" socket to your extension and ratchet. Do not use the socket this time because it will stick to the SP. Tighten the spark plugs in a clockwise direction. Be careful not to over tighten, as the cylinder head is made of aluminum and can be stripped if too much force is applied to it.
  9. The SP wire can now be re-attached to the spark plug.
  10. If you have the coil on plug system mentioned earlier, there are typically two 10mm bolts holding the coil onto the spark plug. Removing these bolts and the coil will give you access to the plugs.
  11. Re-install any plastic covering that was removed.

Job completed. Your engine should run smoother and more efficiently.