White Tipped Spark Plugs: How To Read Spark Plugs

For an engine to run correctly, spark plugs are essential. Since they are consumables, you will need to replace them as soon as possible.

However, in addition to their general wear and tear, spark plugs can be used to identify other issues, and the colors on their bodies may point to a potential engine issue. The high temperatures that spark plugs operate at cause thin, light gray, yellowish, or brown deposits to build upon them.

These hues are natural and are caused by iron oxide and fuel impurities that occur when oxygen is applied to a steel body. If there is a problem, these colors will change.

A spark plug with a white tip indicates that it has burned due to overheating. There is one thing to remember, though—nothing to worry about if the white deposits are comparatively weak.

Since they function at high temperatures, spark plugs frequently develop white deposits. This pale hue can be caused by iron oxide and fuel impurities when oxygen comes into contact with the steel body of the plug.

You may have a more serious issue if the spark plug tip has significant amounts of thick white deposits. Even if the stakes are shiny or wide, you shouldn’t be frightened if you see faint white deposits on your spark plugs and your car has an LPG system.

Regular gas does not contain additives, in contrast to gasoline and diesel, which both have. Its combustion temperature is slightly higher, and the body will develop a tiny white carbon deposit.

Why Do White Buildups Form On The Spark Plugs?

Spark plugs with white deposits are frequently the result of a poor ignition process brought on by either a low fuel-air ratio or no ignition at all. High temperatures cause the light-colored carbon deposits to persist while the darker ones burn off.

Causes And Solutions Of White Spark Plugs

1.     Unstable air-fuel mixture

The engine won’t run at its best in this situation. The air-fuel mixture must be present in the combustion chamber in a specific ratio for complete combustion. Certain parts—such as the intake tightness, injectors, and some sensors—such as the crankshaft sensor, MAP sensor, and others—are in charge of ensuring that this air-fuel mixture is in the right proportion.

When they malfunction, your engine may run on lean air-fuel, preventing it from reaching its usual operating level—ultimately resulting in white or black deposits on the spark plug tips.

2.     Sparks plugs are worn

When damaged or loose, spark plugs have a hard time igniting your air-fuel mixture in the combustion chamber. This mixture detonates due to the ignition delay, causing heat and engine explosion. Additionally, spark plugs with white tips are frequently the result of plugs subjected to such temperatures.

Mechanic removing car spark plugs in engine block.

White deposits on the spark plugs may form if these components malfunction and you utilize low-quality fuel. In this scenario, the engine’s cycle will be disturbed, and performance will be noticeably diminished.

Again, each car requires a unique set of heat-resistant spark plugs. Your engine’s heat range may need help handling an improper spark plug. As a result, the tip of the plug develops white leftovers from too much heat. Another possibility is that you installed spark plugs in your car with a thermal range that is too high.

Although you can try to clean the spark plugs by using higher-quality fuel and additional additives, replacing the spark plugs will be a better option.

3.     The car uses low-quality fuel

Your engine must work harder than usual because of the poor fuel, which always produces too much heat. White residues will develop on their tip if your spark plugs are subjected to such heat. If you use fuel with subpar additives or counterfeit power, white deposits on spark plugs are expected.

In addition to contributing to poor engine performance, this factor will hasten the wear of specific engine components, most notably the oxygen sensor and the catalytic converter, which will both fail considerably more quickly.

As mentioned above, refilling with high-quality fuel and replacing the spark plugs may resolve the problem.

How To Check Spark Plugs For White Deposits

Knowing what is causing the white or black deposits on the spark plugs will help you avoid more severe issues. Spark plugs must be routinely inspected to ensure proper maintenance. To do it, you’ll need the following:

  • Spark plug wrench
  • Flashlight to closely examine the spark plugs’ color, especially in situations where there is little or no light at all
  • Before removing the spark plugs, wipe the wells and cover them for the test

The process is simple and won’t take too long. The main difference is that some models need to remove the high-voltage wires from the plugs first, while others require using an appropriate socket wrench or a head with a screwdriver to remove the fastened individual coils with screws. Remove them one at a time or mark the spark plug wires to avoid confusion.

How To Remove White Deposits From Spark Plugs

Remember that once the issue that initially produced the soot has been resolved, you should clean the spark plugs. The spark plugs can be cleaned and reused if there are only a few deposits, but if there are numerous thick buildups, they will need to be replaced.

There are two ways to remove white deposits from spark plugs; the first is the simplest and requires the following supplies:

  • A coarse metal rust removal brush
  • Fine sandpaper, P 240 and above

Fold the plaque in half and use fine sandpaper to clean the area between the electrodes carefully. Be careful not to damage the spark plugs when doing this. Do not attempt to clean.

Cleaning the spark plugs chemically is another approach you should attempt.

The preferred method for cleaning them without harming the electrodes is as described. For more expensive spark plugs, it works fantastically. What you’ll need for this is:

Spark plug cleaning in a repair shop.
  • Solvents like gasoline, kerosene, acetone
  • Orthophosphoric acid solution
  • Vinegar or ammonium acetate solution of 20%
  • Sanitary plaque removers

Start by using a solvent to degrease the spark plugs, and then add the spark plugs with the electrode in the functioning part to the cleaning solution. Put the plugs in a basin after adding the cleaning agent. After controlling the rate of deposit removal for a few hours, rinse the spark plugs with solvent once more.

The spark plugs can be dried and put into the engine after removing the white deposits. Non-flammable liquids can be heated but not raised to boiling temperatures to quicken chemical reactions. Remember safety, and wear gloves.

Using this method occasionally results in some soot remaining, but only enough to make it simpler to remove using a cloth.


For those unsure what a white tip spark plug denotes: It indicates that your spark plugs have burned due to overheating. The engine will eventually suffer if the cause of these buildups is not found and removed.

This might be caused by defective injectors or carburetors that result in lean gasoline. You could burn out your spark plugs if you use an inadequate or ineffective spark plug and poor fuel.

Repairing the parts accountable for a white-tip spark plug is the sole approach to resolving the issue. Your engine will suffer damage if these components are not fixed because they interact with other elements.

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About Matthew Webb

Hi, I am Matthew! I am a dedicated car nerd! During the day, I am a journalist, at night I enjoy working on my 2 project cars. I have been a car nerd all my life, and am excited to share my knowledge with you!

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