White Deposits on Spark Plugs and How To Remove Them?

Spark plugs are crucial in petrol engines and enable the car to run smoothly. Therefore, it is vital to ensure they are clean to avoid unnecessary replacements and keep them in good condition, hence maximum performance.

White deposits, melted electrodes and blisters at the tip of the insulator are a sign of burned spark plugs, and it shows that the spark plug is running very hot. It is caused by overheating the engine, loose spark plug, wrong spark plug heat range, improper ignition timing, and very lean air to fuel mixture.

It is good to clean your spark plugs and understand when to clean them to avoid accumulating those deposits. However, the best option is to replace dirty and old spark plugs, but if you can’t afford new spark plugs at the moment, cleaning them will help.

Cleaning your spark plugs will help your car run for more thousand miles before you can replace them.

This article will explain what causes white deposits on spark plugs and how to clean them.

White Deposits on Spark Plugs Causes

The debris or the white deposits are primarily a result of overheating due to the flawed process of ignition.

Here are the common causes of white deposits on spark plugs and how to solve them.

The Spark Plugs are Worn-out

If your spark plugs are wearing out, failing, or using low-quality fuel, it accumulates white deposits on the spark plugs. All this reduces the engine’s performance and disrupts the life cycle of the spark plugs.

Solution: Clean the spark plugs by adding extra fuel additives and using good quality oil. Although it will allow you to drive for some extra miles, the best solution here will be replacing the old spark plugs.

Unstable Air to Fuel Mixture

When the air to fuel mixture is not stable, the engine will not function optimally. It can also lead to white deposits accumulating on the spark plugs.

Solution: check the air to fuel mixture intake tightness, injectors, crankshaft and camshaft sensor and MAP sensors and change them.

an image of spark plugs that are faulty with white substances

Use of Low-Quality Fuel

If you use low-quality fuel for your car or harmful additives, you will likely have white deposits on your spark plugs.

Counterfeit fuel also leads to poor engine performance and makes the engine parts wear out faster. The catalytic converter and oxygen sensor are the most affected parts, failing more quickly.

Solution: Refill your car with the fuel of high-quality and suitable fuel additives. Alternatively, you can replace the spark plugs.

How to check spark plugs for white deposits

To check your spark plugs for white deposits, remove them from the engine and examine them closely.

You will need a spark plug wrench to remove them plugs from the engine bay. The only difference between models is that some require the high voltage wiring to be unplugged from the plugs beforehand, while others only need a screwdriver head or socket wrench to remove.

If you see any white deposits, clean the plugs with a wire brush or sandpaper and reinstall them. Be sure to Gap the plugs properly before reinstalling them.

If you find that the white deposits are excessive, it’s a good idea to have your mechanic take a look at the engine to ensure that there aren’t any other issues. Excessive white deposits on the spark plugs can be caused by several things, so it’s important to have a professional diagnose the problem.

Thick white soot deposits on the spark plugs

If you find this type of deposit, it means that coolant or oil may be present in your car engine combustion chamber.

In this situation, you should inspect the engine as quickly as possible; the causes of this problem are generally   cylinder head gaskets and valve seals that must be changed replaced as soon as possible.

Rough white soot on spark plugs, like glossy build-ups, is caused by , additives, untimely spark, improper mixture formation, and  and contaminants in the fuel.

Glossy white deposits on spark plugs

Depending on the situation, coatings on the  plugs can occur in a variety of forms. A spark plug’s ground electrode is usually covered with a gleaming white coating. As a result, engine performance will decline, which might be a sign of more serious problems.

  • The glossy deposits are caused by
  • Lean fuel mixture
  • Fuel octane is improperly balanced
  • Clogged injector nozzles
  • Wrong spark plugs
  • Intake air leaks

As a result, valves and cylinders will overheat, causing pistons & plugs to wear out faster. As a result, the engine oil’s protective properties will decrease faster. When the engine’s power is lowered, there is a danger of a lean mixture, improper ignition, and the appearance of engine knocks.

How to Clean White Deposits on Spark Plugs

To clean your spark plugs, you will need first to remove them from your car. Before you remove them, disconnect the negative terminal of your vehicle’s battery for the sake of your safety.

It is essential to take precautions when handling spark plugs and other components.

Here are the methods for cleaning your spark plugs;

Brush using a Wire Brush

Cleaning your spark plugs with a wire brush is one of the most popular methods.

You scrap all the dirt from the spark plug to clean it in this method. To avoid getting your hands fatigued due to a lot of scrapping, use a table vise clamp.

Also, in case your budget allows you, get an electric wire brush. It will help you clean more efficiently and even faster.

You can also apply gasoline or WD-40 to loosen the debris or white deposits from the spark plugs.

Ultrasonic Cleaner

Using ultrasonic cleaner to clean white deposits from your spark plugs is straightforward.

If you run an automotive shop or love having projects, getting an ultrasonic cleaner is a good investment.

To clean the spark plugs, fill the ultrasonic cleaner with water and cleaning concentrate that you will choose. Dip the spark plugs with the white deposits in the mixture and allow the cleaner to keep running for 15 to 25 minutes at about 50 degrees Celsius.

It will help clean all the carbon deposits and debris without getting tired. After cleaning, allow the spark plugs to dry before installing them back.

Use Soda and Salt

In this method, you require soda and some salt. You can clean so many parts of your car using soda, both exterior and other parts. Soda helps remove rust and other debris, and using soda, you will not have to incur the costs of going to the mechanic.

Here, you will get a container and place your spark plugs inside and then pour soda until it submerges the spark plugs. Then add some salt to help get you perfect results.

This method will take you more time, so perform it when you are not in a hurry for the best results.

The soda and salt will loosen the white deposits and dirt from the spark plugs then you can easily brush them off using a wire brush.

Use a Blow Torch

You will not damage your spark plugs by using a blow torch because they are prone to high temperatures.

Now, get a pair of pliers to hold the spark plugs safely from you. It would be best if you did not use your empty hands for this method because, in the process, the spark plugs get very hot.

With your pliers, use the blow torch on your spark plugs. It helps burn all the excess gasoline, carbon deposits and excess oil from the plugs. Do this for one or two minutes, and the white deposits will be no more.

In this method, avoid cooling the spark plugs with water because they can crack.

So allow the spark plugs to sit on a dry surface for some minutes before you install them back.

Frequently Asked Questions

Can you clean spark plugs without removing them?

No, you can’t! You will need to remove the spark plugs from their containers to access all the white deposits.

Can you clean spark plugs with carb cleaner?

Yes, you can clean inside the spark plugs hole using carburetor cleaner. It helps in dissolving the hard debris and loose materials. After using the carb, you remove the dirt using a compressed air can.

Can you use wd40 to clean spark plugs?

Yes, especially when you want to displace moisture from the spark plugs and the ignition distributors. WD-40 helps remove carbon dioxide residue and any water if your spark plugs are wet.

What causes carbon buildup on spark plugs?

When the air and fuel mixture of your car is very rich, it is an indication that the proportion of the fuel is very high. It leads to incomplete combustion; hence carbon builds up on spark plugs.

Carbon buildup indicates a fuel problem, not a faulty spark plug.

Do fuel additives clean spark plugs?

No, fuel additives or injectors do not help clean the spark plugs in any way.

What does a GREY spark plug mean?

Grey spark plugs indicate that spark plugs are functioning at optimum temperatures and the engine is also working well or in good condition.

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On White Deposits on Spark Plugs

When your car’s spark plugs are clean, they will give you optimum performance. However, if it has white deposits, it will prevent efficient performance. So it is essential to clean your spark plugs when you notice the white deposits or any other debris.

White deposits on spark plugs could result from a variety of reasons. So, before you remove the spark plug and start cleaning it, ensure you identify the source of the debris. If you don’t get the source of the white deposits, it means that your engine will be affected in the long run.

Therefore, use the causes listed in this article and choose your preferred cleaning method; when your spark plugs are clean, they give optimum performance.


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