What Is Dielectric Grease and How Is It Used?

We explain whether you need it or not.

Time Needed: 10+ minutes, depending on project, Difficulty: Beginner, Cost: ~$10

You’ve heard the expression “use the right tool for the job,” right? They’re simple words to live by, especially when you’re working on your car where it’s tempting to use workarounds to get the job done faster and for less money. You might get away with cheaping out on some jobs, but it’s sometimes the simplest things that need to be done right. Grease is one of those things. And Vaseline just won’t cut it.

Dielectric grease should be used to seal and protect various components under your hood. It’s designed to keep water and debris out of electrical circuits, and if you’re not familiar with this type of grease, don’t worry. It’s not a common topic at the dinner table. Car Bible’s editors are here to help you understand what dielectric grease is and when to use it.

Let’s get started.

What Is Dielectric Grease?

Silicone-based dielectric grease is made to protect electrical connections or components from dirt, moisture, and corrosion. It can be used in automotive, marine, and other applications.

Dielectric grease coming out of a tube.
Dielectric grease can be helpful but is not necessary. (Image: Tony Markovich)

The Safety Brief

We want for you to exit the garage with all the fingers you went in with. There’s no need for safety to come third, make it first. To ensure your skin stays unblemished and your bones intact, you’ll want to follow these steps.

  1. Wear gloves and safety glasses during this process. Some greases and other lubricants can damage your skin.
  2. Make sure you disconnect the battery before working with electrical components. 
  3. If you’re unsure of what you’re doing, have the pros work on the electrical connections of your vehicle, getting something wrong can cause big problems.
  4. Make sure that the parts you’re applying grease to won’t corrode or be damaged by the lubricant.

The Tools & Parts You Need

The tools you need to work with dielectric grease will vary, depending on the job. In general, a quick electrical repair job will require:

The Job: How To Use Dielectric Grease

You can use dielectric grease for a variety of applications, including:

  • Trailer connections
  • Battery terminals
  • Spark plugs

Here’s How To Use Dielectric Grease on Spark Plug Boots

  1. Make sure the vehicle is cooled down and parked in a level spot
  2. Remove the spark plug boot and clean both it and the spark plug
  3. Apply a small amount of grease on the inner lip of the spark plug boot using a swab or small wooden spreading tool.
Dielectric grease uses silicone dioxide.
Permatex dielectric grease is made of polydimethylsiloxane and silicone dioxide. (Photo: Tony Markovich)

The Questionnaire

Car Bibles answers all your burning questions.

Q: Can I Use Dielectric Grease On My Car Battery?

A: You can, but keep in mind that the grease doesn’t conduct electricity. It’s best use on your battery is around the outside of the terminals to prevent corrosion.

Q: What Is Dielectric Grease Made From?

A: Dielectric grease is made with silicone oil that has been thickened. The resulting product will be translucent white and viscous, almost like a paste.

Q: What If I Don’t Have Dielectric Grease?

A: No problem! Dielectric grease isn’t a requirement for any electrical system to function properly.

Q: How Do I Remove The Grease When I Need To Clean?

A: Short of getting your hands on an industrial grease remover or solvent, your best bet is to use a high-percentage (70 percent or greater) rubbing alcohol to carefully clean away any excess or old grease. Be careful with the electrical connections, please!

Video Tutorial on Dielectric Grease

Best Places To Buy Tools and Parts to Dielectric Grease?

It can be hard to find the right products to get your project started on the right track, especially when you’re working with electrical components or dielectric grease. Car Bibles’ editors have gathered a few of our favorites to get your project off the ground. They include STUF Waterproofing Grease, Mechanix Gloves, and Kleenguard Nemesis Safety Glasses

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