Is Dielectric Grease Necessary for Spark Plugs? A Complete Guide (2023 – 2024)

Electric connections and components can be protected from corrosion and moisture with dielectric grease, an electrically insulating grease. 

In addition to preventing corrosion and oxidation, dielectric grease can be used to lubricate O-rings and gaskets in electrical enclosures. Dielectric grease is made from a silicone oil base.

The purpose of this article is to explain what dielectric grease is and is dielectric grease necessary for spark plugs as well as some of its drawbacks.

What is Dielectric Grease: Is Dielectric Grease Necessary for Spark Plugs?

Dielectric grease reduces wear and tear on electrical connectors and other electrical equipment. Electrical current cannot flow through it because it contains synthetic oil and non-conductive material.

In this way, sparks can be avoided and corrosion can be prevented. Electrical connections can also be sealed with dielectric grease to prevent water from entering.

Dielectric grease acts as an insulator against moisture and other contaminants when applied to electrical sockets, wires, plugs, and the like. Moreover, it extends the lifespan and reduces the need to replace rubber components by preventing them from drying out and cracking.

It is possible to apply dielectric grease to spark plugs to better insulate them! It is highly recommended to apply dielectric grease to spark plugs, even though it is not necessary, as it prevents corrosion, prevents spark arcing, and prevents the rubber boot of the plug from bonding to the ceramic portion. In addition to keeping the plug moisture-free, it also helps prevent leaks.

The Best Dielectric Grease for Spark Plugs

Best Overall
Permatex 81150 Dielectric Tune-Up Grease

  • All Electrical Connections
  • Spark Plugs
  • Trailer Hitches
Best Overall
Dielectric Grease / Silicone Paste / Waterproof Marine Grease

  • Spark Plugs
  • Multitude Of Uses
  • Great For Many Common Tasks
Best Overall
Dielectric Grease with A Curve Brush, A Straight Brush and A Towel, 100% Silicone Paste, Excellent Lubricant Silicone Grease

  • Electrical Connectors
  • Metal, Rubber, Plastic
  • O Rings

Every product was carefully curated by an Esquire editor. We may earn a commission from these links.

Various materials can be used to make dielectric grease, but silicon dioxide is the most common one. In addition to aluminum oxide, zinc oxide, and titanium dioxide, other ingredients may also be used.

Depending on the manufacturer, the exact composition may vary. Dielectric grease usually combines silicone with a thickener, like polydimethylsiloxane.

If “Dielectric grease” probably means nothing to you if you aren’t a grease monkey or a hard-core roadhead. It can extend the lifespan of spark plugs and other electrical engine components in your vehicle, though you must know what it is and how to use it.

Where to put Dielectric Grease on Spark Plugs?

The best way to ensure that your spark plug is protected is to apply dielectric grease liberally. The use of too much dielectric grease can actually render mechanical connections nonconductive, resulting in engine misfires.

Remember that dielectric grease is non-conductive, which means that it should never be applied directly to wire terminals or sockets, or other electrical joining surfaces.

Dielectric grease must be applied only to the rubber boot where the spark plug meets the ignition coil if you plan to apply it to your spark plugs.

How Often Should You Apply Dielectric Grease?

Spark plugs should be greased with dielectric grease every time they are changed. In this way, corrosion protection will be provided for the new plugs.

Gasoline engines require spark plugs to function properly. The fuel ignites when they generate sparks, which power the engine. The purpose of a spark plug is very simple, but they are crucial for an engine to run properly.

Engines cannot run without them. The electrode and ground straps are the two main components of the spark plug. A spark plug’s electrode is responsible for producing the spark.

An electrical current flows from the electrode to the engine block through a ground strap attached to the metal shell of the spark plug. An electrode’s gap from the ground strap determines the size of a spark. Sparks are larger when there is a larger gap.

Iridium, platinum, and copper are among the materials used in spark plugs. Spark plug longevity is determined by the electrode material.

Spark plugs made of iridium and platinum can last up to 100,000 miles before they need to be replaced. Spark plugs made of copper only last about 20,000 miles.

Related Article: Grease Types and Grades? What You Need to Know [2023 – 2024]

Are there any Drawbacks to Dielectric Grease?

Silicone grease called dielectric grease main purpose is to provide electrical insulation and moisture resistance. Providing protection from corrosion and moisture can be effective, but it can also have some disadvantages.

It is difficult to remove dielectric grease from surfaces, and it attracts dust and dirt as well. Grease that gets into sensitive electrical components or connections can cause problems.

In addition to hardening over time, dielectric grease can also be difficult to remove from surfaces. Be sure to clean any excess dielectric grease from surfaces and keep it away from sensitive areas if you’re using it.

If you are concerned about these drawbacks, you may want to consider a different type of grease.


1. Can you install spark plugs without dielectric grease?

 In spite of not being necessary, it’s strongly recommended to apply dielectric grease to spark plugs in order to maintain their corrosion resistance, prevent arcing, and prevent the rubber boot from adhering to the ceramic portion.

2. Will dielectric grease cause a short?

The misuse of grease could lead to short circuits between pins.

3. Is dielectric grease just silicone?

Silicone oil and thickener are combined to create silicone grease, also known as dielectric grease. Polydimethylsiloxane (PDMS) and amorphous fumed silica are the most common silicone oil and thickener, respectively.


An electrical lubricant called dielectric grease is specifically designed for electrical applications. The silicone base, as well as the insulating compound, make this product heat- and cold-resistant.

Spark plugs are usually greased with dielectric grease to prevent corrosion and misfires. Taking spark plugs out and reinstalling them is also easier with it.

It is important to note, however, that not all spark plugs require dielectric grease. Typically, the only plugs that need to be coated are those exposed to the elements, such as outdoor engines.

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