Dielectric grease, or tune-up grease, is a silicone-based grease that repels moisture and protects electrical connections against corrosion. It is also used to keep dirt, water, and other elements out of electrical connections. It has many uses, including automotive tune-ups, home electrical work, and recreational vehicle wiring. Dielectric grease does not dissolve in most liquids, so it is good for marine and outdoor applications. You can use this grease to lubricate the rubber parts of electrical connectors, spark plug wires, and to protect electrical connections on your boat or recreational vehicle from corrosion. Since dielectric grease is a silicone grease, it should not be used on silicone-based rubbers or plastics, as it will break them down over time. The grease does not conduct electricity, so it shouldn’t be applied directly to the mating surfaces (pins and sockets) of an electrical connection.
How to Use Dielectric Grease
To use dielectric grease during an automotive tune-up on a gasoline or diesel engine, apply a bit of the grease to the end of the rubber boot on a spark plug wire and spread it around so it is just covering the inside of the lip. This will make it easier to slide the boot over the ceramic insulator on the spark plug and ensure that there is a water-tight seal around the plug that will protect the connection from water and dirt.
You can also apply dielectric grease to the gaskets on multi-pin connectors that are typical in the electrical systems of boats and recreational vehicles. Simply take a small dab of the grease and smear it around the gasket on both sides (if possible) before inserting the gasket around the connection.
Dielectric grease can also be applied to the metal parts of virtually any electrical connection that will be exposed to the elements to serve as a sealant that protects the connection from contamination and corrosion. This should be done very carefully, as the grease will cut off the flow of electricity through the connection if some of it is left between the mating surfaces. As always, we recommend working with your local auto mechanic when doing any maintenance on your vehicle.