What Is Dielectric Grease? More Importantly, Are You Using It Wrong?

There are a lot of confusing terms and components you may come across when you’re working on your car, and while there’s nothing quite as puzzling as a flux capacitor in your everyday motor, some parts can sound equally perplexing. One such workshop regular you may not be all too familiar with is dielectric grease, which isn’t essential for your toolbox but can help prolong the lifespan of some components.

Dielectric grease, as you might expect, is a type of grease that can be used in several parts of your car. It’s usually found around things like light bulbs and spark plugs, and not so much with typically lubricated components such as bearings and gears. The reason dielectric grease isn’t used on moving parts comes down to its makeup. The material “is a viscous non-conductive waterproof substance used to protect electrical connections from corrosion and dirt,” explains The Drive.

Traditionally, the sticky substance is made with a silicone base and a thickening ingredient. The base is usually polydimethylsiloxane, while the thickener may be something called amorphous fumed silica. This makeup means that dielectric grease doesn’t conduct electricity, as you might have thought, and instead it insulates electrical components.

If it’s not being used to lubricate gears or bearings, what is dielectric grease used for? Well, it’s all about keeping water and moisture out of your electrical systems, explains MotorTrend:

When applied properly to electrical sockets, plug wires, or fittings with a good, tight mechanical connection, dielectric grease is a fantastic means to keep water and moisture out of your electrical system, prevents rubber gaskets from drying and cracking and seizing, and helps mitigate any dust or alkaline contamination that could cause corrosion and early deterioration of your wiring and connectors.

If used around electrical connections, the insulating properties of dielectric grease doesn’t mean that it will worsen a connection. When you use a small amount of the grease, it will be displaced by the tight fitting connections, so it will surround them rather than interfere with them. This means that the grease forms a protective barrier around any connection and won’t get in the way of the passing current. In other words, dielectric grease lubes and seals the components without negatively affecting the electrical system connections.

As you might have guessed, dielectric grease is best used sparingly, as huge blobs of the stuff will be both messy and wasteful. It’s best applied using something like a cotton bud, which can smear a small amount of grease over a terminal or connection.

If you do this, dielectric grease can insulate electrical connections, protect against corrosion and water damage, and keep dirt and grime out of important terminals. These kinds of uses are most advantageous around things like battery terminals, spark plugs, bulb sockets, and even trailer connectors. If you use it safely and sparingly, dielectric grease can help extend the life of these components, which will mean fewer headaches down the road.

If this left you with a hankering to find out more about the workings of your motor, head here to find out more about the transmission fluid in your car or here if you want to know how to spruce up the trim on your car.