How to Change Spark Plugs? Easy Steps, Easy Tips

Basic knowledge of the key components such as; the engine, tires, and battery, is a good start. But understanding how to maintain these key components is even better.

Let’s look at your engines spark plugs or more specifically, how to replace spark plugs for optimum performance.

What is spark plug?

To give you some idea of what a spark plug is, just visualize a tiny but powerful lightning bolt. With each bolt of lightning, an explosion of fuel and air is set off in your engines cylinder chamber. Now visualize this across multiple cylinders of the engine and you have a good idea of what makes your engine tick.

How spark plug work explanation video:

When do you need to change spark plugs?

With the technology in vehicles today, the chance of a spark plug going bad is remote, but it can happen. Indeed, what happens when a spark plug goes bad is an engine misfire, loss of power or degraded fuel economy. Any of these symptoms could be warning signs of bad spark plugs.

So now you may be thinking, how do I know if my spark plugs need changing? The easiest way is to look at your owner’s manual and follow the recommended schedule.

What are the benefits of changing spark plugs? This can be answered quite simply. Changing the spark plugs according to the owner’s manual recommendation will ensure easy starts and proper acceleration of your car.

how to change spark plugs
Toyota Spark Plug Part.

Do you need a special tool to change spark plugs?

To change a spark plug you will need a socket wrench, spark plug socket (5/8 or 13/16 inches) and an extension. There are other tools that may be useful, but they are not critical. These include the following:

  • Socket with a rubber insert to hold the plug in the socket
  • Gapping tool to make sure the gap is correct
  • Universal joint to get in the hard to reach places
  • Adjustable pliers are always a good idea
  • Tube of anti-seize crème to put on plug thread before installation

If you are confident of your mechanical ability, then removing spark plugs and installing new ones is very straightforward. If you’re not comfortable getting under the hood, then it might be a good idea to let a professional do it.

Step by steps guide how to change spark plugs

The process of how to change spark plugs and wires (wires optional) is very easy if you have the right tools. The rule of thumb is to replace spark plugs at around 30,000 miles. If you are not sure then refer to your owner’s manual for guidance.  So, now that you are prepared, let’s replace some spark plugs using the following step-by-step guide:

  1. Refer to your owner’s manual for the exact location of each spark plug. Hint: each plug will have a wire from the distributor attached to it.
  2. Clean the area around the plug wire and plug on each cylinder so that no dirt will fall into the cylinder opening.
  3. Now remove the wire from the spark plug on the first cylinder. You can start with any cylinder, but it is a good idea to do each spark plug one at a time. This is especially important if you are also replacing the wire. Hint: do not pull on the wire, only pull gently on the connector to remove it.
  4. Once the spark plug is exposed, you can now use the socket wrench and socket to remove the spark plug. Hint: remember counterclockwise to loosen and clockwise to tighten.
  5. To install the new spark plug it is a good idea to dab a little anti-seize crème on the thread which will make it easier to remove the next time you want to replace it.
  6. It is a good idea to check the gap of the spark plug even though it should be correct from the factory.
  7. Now place the plug into the socket and make sure it is snugly seated.
  8. Insert the plug into the cylinder head hole opening and gently start to screw it in. Hint: it should turn easily if you encounter any resistance reverse direction to remove the plug and fix the problem.
  9. If the plug seats normally then go ahead and tighten it until it is snug but take care not to over tighten it.
  10. You can now replace the wire and plastic boot to reconnect the spark plug to the distributor.

Now… You’re done! Now move on to the next spark plug and repeat the process.

Tips to change spark plugs

If you are doing this yourself then here are a few tips that will make the job easier:

  • Replace spark plugs one at a time to ensure that you do not accidentally mix up the wires connected to the distributor.
  • Check the gap on the spark plug to be sure it is within factory specs.
  • If the spark plug is in a hard to reach part of the engine, just insert it into one end of a rubber hose and maneuver it into the cylinder hole opening.
  • When installing the new plugs do not over tighten it.
  • Do not pull on the wire, only pull gently on the connector to remove it.
  • When installing the new spark plug it should turn easily, if you encounter any resistance reverse direction to remove the plug and fix the problem.

Want to know more about your car…

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