How to Clean Spark Plug Hole? The Best Ways

It’s not every day you need to clean the spark plug holes, but you must do it when it happens. Spark plugs are a critical component of your vehicle. And they’re the ones responsible for getting your engine running. If dirt or debris is interfering with the performance of these plugs, then this can cause some problems like misfiring or poor acceleration.

So, if you want to make sure your car stays in tip-top shape, take a few minutes out of your day to read this blog post on how to clean spark plug hole!

clean spark plug hole

What Happens If Dirt Falls in Spark Plug Hole?

If dirt falls into the spark plug hole, it can create several problems, like:


When the spark plugs don’t fire correctly, it can cause the engine to run rough and can even lead to it not starting at all. We suggest to always use better spark plugs in your car.

Poor Acceleration

Dirty spark plugs can impede your car’s ability to accelerate, making it harder to get up to speed.

Excess Fuel Consumption

Not only will your car not run as smoothly, but it will also guzzle down more fuel as a result.

Damage to the Engine

In extreme cases, if dirt and debris are allowed to build up in the spark plug hole, it can cause extensive damage to the engine. Thus always use better quality like NGK Plugs in your vehicle engine.

Items Required to Clean Spark Plug Hole

There are some spark plug cleaning tool you will require to clean the spark plug threads. These include:

  1. A soft washing brush.
  2. Air gun.
  3. Carb cleaner.
  4. Wrench.
  5. Screwdriver.
  6. Safety glass.

How to clean spark plug hole?

Now that you know why cleaning the spark plug hole is essential. Here is the best way to clean:

1. Remove Battery’s Negative Terminal

Safety first! Before you get started, make sure to take off the negative terminal on your battery. This is a pretty standard procedure for mechanics and other car repairs, so don’t skip it! To do this, loosen the nut and hold it in place with a wrench. Once removing the negative terminal, you can stand back and get ready to clean your spark plugs and put the correct order of spark plug wires after cleaning! You should also know the number of spark plugs in your car.

2. Find the Spark Plugs

To find out which spark plug hole you need to clean, open the hood and locate your spark plugs. Each one is a little different so keep an eye out for things that look like cylinders with wires running into them! You can find these in the following places:

  1. On top of the engine, close to or on top of the cylinder head.
  2. Directly underneath the engine.
  3. At the back, near the firewall.
  4. Between cylinders and valve covers.

If you aren’t sure which spark plugs to clean, it’s usually best to start from the front and work your way towards the vehicle’s rear. This way, you will already know where the spark plugs are if you need to do a little work on them. You can also clean spark plugs at a time to get better performance.

3. Use Air Gun to Remove Debris

Once you find the hole for the spark plug, blow out the dirt and debris with your air gun. You can also insert your cleaning brush into the plug hole and gently sweep away the grime with it! If you do not have an air gun, you can stick some carb cleaner (defined below) in through the air valve on top of each cylinder.

Be careful while doing this because excessive pressure could damage your engine or even blow it up!

4. Spray Carb Cleaner in Spark Plug Hole

If you’re using an air gun, you can skip this step. But if you’re not, then it’s time to break out the carb cleaner! Simply spray a healthy amount of plug cleaner into each spark plug hole and allow it to sit for a few minutes. Cleaning spark plugs using Spark Plug Cleaner will help dissolve any leftover dirt or debris. You can use spark plug hole threads cleaner for cleaning without any hesitation.

5. Wipe Out Spark Plug Hole with Rag

After the carb cleaner has had enough time to break down anything in there, it’s time to wipe out spark plug hole clean! To do this, you will need a rag and some water. Dip the rag into your bucket of water and then squeeze it out so that it isn’t dripping wet. Then use this damp rag to wipe away whatever is left in the spark plug hole!

6. Replace Negative Battery Terminal

Now that you’ve finished cleaning out, it’s time to put your negative battery terminal back on. This is pretty simple, but if you do not feel confident doing this yourself, bring it to a mechanic or car repair shop and let them take care of it for you. Once the negative terminal has been put back in its place and properly tightened down, your car should be all set!


1. Can You Clean Spark Plugs with the Carb Cleaner?

Yes, carb cleaner cleaning spark plugs will help dissolve any leftover dirt or debris.

spark plug hole cleaning

2. Can You Spray WD40 in Spark Plug Hole?

It depends. WD40 can be used as a temporary fix for a dirty or fouled spark plug. But it’s not recommended. If you are having trouble getting the gunk out of your spark plug hole, spray WD40 in there and wait for a few minutes before trying to clean it out. Just be careful not to use too much, as WD40 can harm your engine if you overdo it!

3. Can You Put Gas in Spark Plug Hole?

It is never a good idea to put gasoline in spark plug holes or anywhere else on your engine! It may cause you to lock hydraulically.

4. Can You Clean and Reuse the Fouled Spark Plug?

It is feasible to clean and reuse a fouled spark plug. But it is not recommended. The fouled spark plug has been covered in carbon, oil, or other debris. If you try to clean and reuse the fouled spark plug, there is a good chance that it will not work correctly and could potentially damage your car.


That’s all on how to clean spark plug hole! If cleaning the spark plug hole is something you struggle with, try cleaning it every time you change your spark plugs. This way, they will function properly and reduce engine overheating in the future.

Also, cleaning spark plugs regularly will help you avoid the hassle of having to go through an engine replacement later on! If cleaning a spark plugs is something you cannot do yourself, take your car to a mechanic and ask them about cleaning out the spark plug hole threads.


Shafiqule Islam is a graduated Mechanical Engineer. He has both on hand and managerial job experience of 15 years in automobile maintenance field. He served as Captain in Electrical and Mechanical Engineering Corp of Army, Technical Head in Taxi Cab business, Head of Plant in Car assembly plant. He is writing automotive contents to share his expertise knowledge to car lovers for solving their vehicle issues.

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