What To Spray In Spark Plug Hole

Spraying in the spark plug hole is a common practice among car enthusiasts and mechanics, but why is it done and what exactly should you spray? Let’s dive into this intriguing topic that may initially seem complex but can actually be quite straightforward.

In this guide, we’ll explore the fundamentals of what to spray in a spark plug hole. From understanding the purpose behind this practice to identifying the correct products to use, we aim to provide a comprehensive guide to help you navigate this aspect of vehicle maintenance with ease. Whether you’re a seasoned mechanic or a car owner looking to learn more about the inner workings of your vehicle, this topic is sure to pique your interest.

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If your car is having trouble starting, it might be time to give the spark plugs a little bit of help. By spraying a little WD-40 or similar product into the spark plug hole, you can help lubricate the plugs and make them easier to remove. Just be sure to use a straw or other narrow nozzle so that you don’t accidentally get any WD-40 on other parts of the engine.

Cleaning Pistons Through Spark Plug Hole

Cleaning Pistons Through Spark Plug Hole It is a common practice to clean the top of the pistons through the spark plug hole. This is an effective way to remove carbon build-up and other deposits that can accumulate on the piston crown. The following steps outline the procedure for cleaning pistons through the spark plug hole:

1. Remove all spark plugs from the engine. This will give you access to the piston tops.

2. Spray a liberal amount of cleaner into each cylinder through the spark plug hole. You can use carburetor cleaner, brake cleaner, or any other type of degreaser.

3. Let the cleaner soak for several minutes to loosen up any deposits on the pistons.

4. Use a brush (toothbrush, paintbrush, etc.) to scrub away any remaining residue from the piston tops. Be sure to get into all of the nooks and crannies!

What to Spray in Spark Plug Hole

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What Can You Spray in a Spark Plug Hole to Clean It?

If you’re looking to clean a spark plug hole, there are a few different options you can choose from. You can either use compressed air, brake cleaner, or carburetor cleaner. All of these options will do a good job of cleaning out the hole and getting rid of any build-up that may be present.

Compressed air is probably the most commonly used method for cleaning spark plug holes. All you need is a can of compressed air and a straw. Simply insert the straw into the spark plug hole and spray away. The high-pressure air will blast away any dirt or grime that’s clinging to the sides of the hole. A brake cleaner is another effective option for cleaning spark plug holes. Brake cleaner is designed to clean brake parts, so it’s tough on dirt and grime.

Just spray some brake cleaner into the spark plug hole and let it sit for a few minutes before wiping it clean with a rag. Carburetor cleaner is also an option you can use to clean spark plug holes. Carburetor cleaners are designed to clean carburetors, so they’re also tough on dirt and grime.

Can You Spray Starting Fluid in a Spark Plug Hole?

Spraying starting fluid into a spark plug hole is not advisable and can actually damage your engine. The chemicals in the starting fluid are highly combustible and can cause the plugs to overheat, potentially causing a fire. If your engine is having trouble starting, it’s best to consult a mechanic to diagnose the problem.

What To Spray In Spark Plug Hole

Can You Put Wd-40 in Spark Plug Hole?

No, you should not put WD-40 in a spark plug hole. WD-40 is a lubricant and solvent, which means it can leave behind residue that could potentially interfere with the ignition process. Additionally, WD-40 is flammable, so using it around spark plugs could create a fire hazard.

Should You Put Oil in Spark Plug Hole?

If your car has a lot of miles on it, you may be wondering if you should put oil in the spark plug hole. The answer is no; you should not put oil in the spark plug hole. Oil can damage the electrode and cause misfires. Plus, it can make a mess and is difficult to clean up. If you’re looking to add oil to your car, there are other places where it’s more appropriate to do so.

What To Spray In Spark Plug Hole

Frequently Asked Questions [FAQs]

What should I spray in a spark plug hole?

You should spray a small amount of engine starter fluid or fogging oil into the spark plug hole. This can help to lubricate the cylinder walls and protect them from rust and corrosion, especially during extended periods of inactivity. It’s essential to ensure the product is suitable for your engine type and to follow the manufacturer’s instructions.

Why would I need to spray something in my spark plug hole?

Spraying a lubricant or protective substance in your spark plug hole can help to prevent rust and corrosion in the cylinder and piston area. This is especially beneficial if the engine will not be used for a prolonged period. It can also assist in starting an engine that has been dormant for a while.

Can I use WD-40 in my spark plug hole?

Yes, you can use WD-40 in your spark plug hole as a temporary solution for removing moisture and preventing rust. However, it’s not recommended for long-term storage or lubrication, as it may not provide sufficient protection against corrosion. For these purposes, a dedicated engine fogging oil or lubricant is typically more effective.

How much should I spray in the spark plug hole?

While the amount can vary depending on the specific product and engine size, generally, a brief two to three-second spray into each spark plug hole is sufficient. It’s important not to overdo it, as this could potentially flood the engine. Always follow the product manufacturer’s instructions for the best results.

What happens if I spray too much in the spark plug hole?

If you spray too much fluid into the spark plug hole, you risk flooding the engine. This can make it difficult to start the engine and, in severe cases, can cause hydraulic lock, which can lead to engine damage. Always use the minimal effective amount of fluid and follow the manufacturer’s instructions.


If your car isn’t starting and you suspect that it may be due to a problem with the spark plugs, there are a few things you can try before taking it to a mechanic. One is to spray some WD-40 or other lubricant into the spark plug hole. This may help if the problem is that the plug is seized in the hole.

Another possibility is that the spark plug gap is too wide. You can try adjusting it yourself or replacing the plug with one that has the correct gap. Finally, if none of these solutions work, it’s time to call a tow truck and take your car to a professional!