How to Put Dielectric Grease on Spark plugs?

A spark plug refers to an eclectic device that ignites the combustion needed to start your vehicle. Putting dielectric grease regularly on the spark plugs is important because it ensures the optimal performance and longevity of this electrical device. Read more about “dielectric grease on spark plugs”.

Although dielectric grease produces better results for spark plugs, it can catch fire if it is not applied properly. In that case, having knowledge about how do you put dielectric grease on spark plugs is a must.

To put dielectric grease on spark plugs, first, gather a cotton swab and the grease. Apply a thin layer inside the spark plug boot, using a circular motion for even distribution. Optionally, apply a thin coat to the ceramic portion of the spark plug, but avoid the metal terminal.

Do not use grease on the distributor or coil end. Besides, I have more tricks for you in the later part of this guide. Stay connected and learn how I put the dielectric grease on spark plugs. Let’s get started.

What is dielectric grease and what do I use it for?

What is dielectric grease and what do I use it for?

Dielectric grease is a silicone-based compound used to lubricate and protect electrical connections. It helps to prevent the conductive materials from moisture or corrosion damage. Not only it protects, but it also improves the conductivity of the conductors for a better supply of current.

You can put the dielectric grease on any conductor, from a spark plug to the battery terminals. It can be the best solution to ensure proper conductance in wet or harsh conditions.

Also Read: The Right Spark Plug Socket Sizes

Why should I grease spark plugs?

Typically, dielectric grease is used to lubricate spark plugs properly and prevent corrosion for better conductance. However, it can benefit you in many ways.

Here I have listed a few major benefits that may convince you to essentially put dielectric grease on spark plugs.

Corrosion Prevention

A thin layer of grease to the spark plug threads can help prevent corrosion and seizing of the plug. It also makes it easier to remove when needed.

Heat Dissipation

Grease can act as a heat conductor, keeping heat away from the spark plug. It also reduces the risk of overheating and improves overall performance.

Moisture Protection

Grease can act as a barrier against moisture and humidity. It prevents wetness from reaching the spark plug and causing damage.

Electrode Protection

Grease also helps to protect the electrode from wear and tear. It reduces the risk of damage and extends spark plug life.


Grease also acts as a sealant. It restricts the oil and other particles from entering in the combustion chamber. So, it helps to improve the overall performance of the engine.

Easy Installation

Grease can make installation and removal of the spark plug easier. It also reduces the risk of cross-threading and damage to the threads.

How to Put Dielectric Grease on Spark Plugs [ Step-by-Step guide]

How to Put Dielectric Grease on Spark Plugs

Things You Need:

Things you need for applying dielectric grease to spark plugs:

  • Dielectric grease
  • Cotton swabs (for application)
  • Spark plug boot puller (optional, for easier removal of the boots)
  • Latex gloves (optional, for cleanliness)
  • Paper towels (for cleaning any excess grease)
  • Spark plug wire set (for replacing old or damaged wires, if necessary)

Steps to Follow- Applying Dielectric Grease on Spark Plugs

Step 1: Prepare dielectric grease

First, prepare the dielectric grease to put on the spark plug. You will need a cotton swab dielectric grease. You have many options, but I recommend Versachem 15339 Dielectric Connector Grease for better performance.

To prepare the dielectric grease, remove the grease bottle cap and take it out in a small container. If possible, use a brush and mix it well for better application.

Step 2: Apply the dielectric grease to the inside of the spark plug boot

Start with applying the grease to the inside of the spark plug boot. Now take a cotton swab, and dip the swab into the grease.

Now, gently apply the grease on the spark plug boot. Be careful here because it may harm the plugs if you use them too much. Only a thin layer is enough.

Step 3: Apply grease evenly

Make sure you are applying dielectric grease evenly. For this, you can use a circular motion and ensure that grease is distributed evenly. Make sure it covers all the inside portions.

Even the application of the grease will help prevent arcing. It also ensures the spark plug will perform efficiently.

Step 4: Avoid applying on metal terminals

For better protection, applying a thin coat of dielectric grease is best. Not only the thin coat but also ensure you are applying over the ceramic material.

Never apply the dielectric grease over the metal terminals. Otherwise, it may cause fire when working.

Step 5: Avoid applying on the distributor or coil end of the spark plug wires

While applying the grease to the spark plug, avoid applying it on the distributor or coil end of the spark plug wires. If you mistakenly apply the grease on these parts, it may increase the resistance.

You may experience misfiring, overheating, or other problems if the resistance increases. So, be careful and only apply the grease only to the inside of the spark plug boot and the ceramic portion.

Common mistakes to Avoid while applying Grease

Common mistakes to Avoid while applying Grease
  • Avoid over-applying it can cause melting of the grease and may cause engine damage.
  • Never apply grease to the porcelain insulator; it can cause misfires.
  • Always use the correct grease. If apply the wrong type of grease it can cause corrosion or reduce conductivity.
  • You must clean the spark plug before applying grease. Failing to clean the spark plug before applying grease can reduce its effectiveness.
  • Do not apply grease over the threads. It can cause them to loosen and potentially damage the engine.
  • Always apply gently. Applying too much force may tighten the spark plug and it may cause it to break.
  • Applying grease to the distributor cap can cause it to malfunction.

Safety Tips:

  • Wear protective gloves and eye gear.
  • Ensure the engine is off and cool before applying grease.
  • Clean the spark plug area to remove any debris.
  • Apply a thin layer of grease on the spark plug threads and inside the boot.
  • Avoid over-application of grease as it may cause damage.
  • Reinstall the spark plugs carefully and torque them to the manufacturer’s specifications.
  • Clean up any excess grease around the spark plug area.

What is the best dielectric grease for spark plugs?

What is the best dielectric grease for spark plugs?

Dielectric grease for the spark plugs comes in a variety of options. But I have picked the two most reliable options for you. You will find them perfect because they perform well and are also affordable.

  1. Super Lube 91003 Silicone High-Dielectric and Vacuum Grease

The Super Lube Silicone Dielectric and Vacuum Grease is a specially formulated silicone compound. It seals, protects, and insulates electrical components and connectors. It makes it ideal for spark plug boots.  The grease is waterproof and provides a barrier against moisture and other contaminants. So, you will find it outperforms both vacuum and pressure systems.

  • Versachem 15309 Dielectric Spark Plug Boot Grease

It is a silicone-based compound that provides superior protection against heat, moisture, and contaminants. So, it may be ideal for spark plug boots. It strengthens electrical connections by reducing voltage leaks, arcing, and misfires. It is compatible with all heavy-duty trucks in compliance with standard protocols (J1587, J1939, and J1708).


How often should I apply dielectric grease?

Dielectric grease should be applied sparingly and only when needed. Its application is affected by different factors such as the routine of using vehicles, conditions, or outside weather. However,

It is recommended to apply it during routine maintenance and whenever electrical connections are disturbed or exposed to moisture.

Can I use dielectric grease on other electrical components?

Dielectric grease can be used on other electrical components like connectors, switches, and relays. It equally benefits them and protects them from corrosion and moisture. However, it should not be used on electrical contacts where low resistance is necessary for proper function.

Can dielectric grease cause a misfire?

No, dielectric grease does not cause misfires if you apply a thin coat. Generally, dielectric grease is applied to prevent misfires. It insulates and protects electrical connections from moisture and corrosion. However, if you applied thickly, then it may lead to poor electrical conductivity, which may cause misfires or other issues.

What happens if I apply too much dielectric grease? If you apply too much dielectric grease, it may attract dust and dirt. It can cause many electrical problems. It may create a barrier between contacts and prevent them from making proper electrical connections. It can also increase the resistance that may lead to malfunctioning of the equipment.