How to Clean a Spark Plug

A spark plug is a tiny little device that is used to deliver an electric current from the ignition to the combustion chamber of an engine. They are used to jump vehicles into life, no matter how large or small, including cars, lawnmowers, and generators.

As you can see, the small spark plug has an incredibly large job to fulfill, so it’s important to clean it properly when it is due. Therefore, it’s also very vital that you know how to tell when your spark plug needs cleaning.

Some people would go as far as to say that the spark plug is one of the most hardworking elements of a vehicle, so you need to ensure that you’re taking care of it. If your tires were to lose air, you’d pump them up … right?

So how come so many of us tend to neglect the thing that allows our engine to ignite and turn on? Our article today is going to attempt to help you to learn why this is so important, how you’d go about seeing the warning signs, and how to actually clean the spark plug.

Dirty Spark Plugs

You might be thinking why would the spark plugs get dirty? Well, it’s just like any other component on your vehicle – if it’s exposed to harsh elements for a prolonged period of time, it’s bound to get dirty sooner or later.

A common cause is that the carburetor is not working correctly and therefore offsetting the air-to-gas ratio. Alternatively, it could be an indicator that the valve seals are damaged or there is a leak somewhere in the combustion chambers.

For this reason, it’s pretty important to know when your spark plug is dirty as it could be a big indicator that a larger problem is on the horizon.

Dirty Spark Plug Indicators

Removing the spark plug will be the easiest way to determine whether you’ll need to clean it or not. This is simple enough and very quick to do, so it won’t take too much time to remove to have a quick look. First, you’ll need some masking tape or labels to ensure that you don’t mix up the small leads.

(Trust us, this is a very necessary step!). Now remove the spark plug with the lead caps to prevent damaging the leads themselves. You should now clean around the plugs to avoid any dirt from getting within the plug holes, as this could cause more issues for you down the line.

There are specialized tools that you can get for spark plugs, so make sure that you have some of these handy for the removal process. Take the spanner and fit it around the spark plug, ensuring that it is perfectly straight. Trying to remove the plug with an unbalanced spanner could cause damage to the plugs, which is not what you want.

Once you’re happy with the alignment of your spanner, you can slowly begin to unscrew the spark plug. Do so until it falls out gently onto your hand. Here you’ll be able to see whether it’s dirty or not. Spark plugs are generally a mixture of white and silver, so if the coloring is grey or black it should be cleaned before putting it back in.

How to Clean a Spark Plug

Now that you’ve established that your spark plug needs cleaning, there are a few different methods of how you could go about it.

Let’s take a look at four of the most common methods of cleaning the spark plug.


Using heat from a blowtorch is one of the quickest methods of cleaning your spark plugs, so if you have the means and equipment, this could be an excellent option for you. Make sure you hold the spark plug with pliers to avoid burning your hands, and we’d advise you to use heat-protective gloves.

Make sure your pliers are secure enough to keep the plug steady, but not too secure that it damages the plug. Now power your blow torch up and hold it up to the end of the plug until the metal glows red. This will burn off the carbon and the majority of the dirt from the plug.

Once the plug is glowing, remove it from the heat and wait a few minutes until the metal cools down. Once the plug cools completely, you can feel free to reinstall it.

Abrasive Materials

Sandpaper is another great method of cleaning the more intricate areas of the spark plug. If the electrode is black, you can use sandpaper to wear away this dirt until the metal coloring has reappeared.

If the threads on the plug are dirty, you can use a metal brush to clean these. Make sure that the wire brush is brushing alongside the threads to avoid them from becoming damaged. Move the wire brush all around the plug to ensure the threads are clean the entire way around.

Clean the entire plug with brake cleaner once you’re finished with the abrasives. If the spark plug is very dirty, you can use the brake cleaner alongside the wire brush to give it a helping hand. Just be careful not to damage the spark plug.

Replacing the Clean Spark Plug

Now that you’ve cleaned the spark plug, make sure that you set the gap between the electrode and the plug to fit inside your vehicle. The gap measurement will be inside the owner’s manual for your vehicle, so don’t guess this measurement!

Now you can screw the spark plug back into the spark holes. Pay particular attention to the feeling of this – if it’s not screwing in easily, you might have an issue with the alignment. Stop trying to screw it in and start over to avoid damaging the plug.

Once the plug is screwed in by hand, you’ll need to tighten it with a socket wrench. This ensures that the spark plug stays in place and doesn’t become ineffective too soon. Make sure that you don’t over tighten the plug, either!

Now reconnect the wires. See, we told you those labels on the leads would come in handy! Once these have successfully popped into place, you’re all finished with the cleaning process of your spark plugs.

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