06/09/2026 by Jay Hatton
Today, there is an extensive array of general use greases available to purchase from trusted manufacturers like Molykote and Fuchs.
However, options also exist with formulas that make them suited for use in specific applications and compatible with materials used to create equipment components, like dielectric grease.
Sometimes referred to as “silicone grease” or “tune-up grease”, dielectric grease is a silicone-based product that effectively repels moisture and can protect electrical components from corrosion. Its other uses include keeping water, dirt and other elements back from electrical connections, but its formulation also means it is an excellent option when rubber components or systems that contain them require a lubricant that is safe to use.
Here, we lift the lid on dielectric grease and its properties and benefits while examining how it works safely with rubber.
What is dielectric grease?
With a silicone-base, dielectric grease is a non-conductive compound that can supply an efficient seal against a range of contamination and corrosion. Its formulation includes silicone, making it resistant to heat and moisture, and a thickening agent called silica, which gives the grease its gel-like consistency, ensuring it remains in place.
In appearance, dielectric grease is typically clear, milky white or translucent. It is safe to use on both rubber and plastic components, unlike greases with a mineral oil or petroleum base. It is an effective electrical insulator, which means it doesn’t conduct electricity, and it is often used in electrical connectors. While it is often used in such applications, its silicone base means it is also ideal for lubricating gaskets, O-rings and other common rubber parts.
Why lubricating rubber correctly is key
Proper lubrication reduces friction, prevents cracking and can extend the active service life of rubber seals, gaskets and O-rings.
Silicone-based lubricants like dielectric grease are water resistant and chemically inert. They are also safe for almost all types of rubber across a wide temperature range (from -40°C to 200°C and above).
Petroleum-based lubrication should always be avoided when maintaining rubber. Standard engine oil, mineral oils and basic petroleum jelly can all cause natural rubber and synthetic solutions, like nitrile and neoprene, to degrade, dry out or swell.
When applying lubricants to rubber, a thin and uniform film is the best practice. This method reduces surface friction and prevents rubber from cutting, pinching and tearing when parts are being installed during assembly. Correct lubrication lets gaskets and O-rings slide easily into their proper final positions.
High-quality dielectric grease can block oxygen, moisture and UV rays that cause cracking and dry rot. Before repeat applications of fresh grease, the best practice is to wipe away any dust, dirt or old debris.
Why does dielectric grease work so well on rubber components?
Dielectric grease can prevent fusing and sticking. This means it stops components like rubber coil packs, wire covers and spark plug boots from baking onto heated metal and ceramic parts over time.
The grease acts as a lubricant, making it excellent for ensuring rubber weatherstripping, gaskets and seals are easier to slide together or push into place. It also reduces friction, ensuring rubber parts experience less wear and tear, prolonging their service lifespan.
As it is silicone-based, dielectric grease helps rubber stay pliable and stops it from cracking or becoming dried out. Chemically inert, it doesn’t impact the structural integrity of rubber, unlike many other types of grease. It also creates a water-repellent barrier on electrical connectors and gaskets, stopping dirt and moisture from causing corrosion.
Key cautions when using dielectric grease
While applying dielectric grease on standard rubber is considered safe, adding it incorrectly can draw dirt, lock in pressure and degrade certain materials. As a result, it is important to check product labels and assess material compatibility before use.
For instance, you should never use dielectric grease on specialised plastics or silicone rubber, as it can lead to swelling and degradation over time.
Finally, never load the inside of waterproof connectors with dielectric grease. The trapped pressure and volume can prevent the connectors from latching fully. Instead, apply grease to the outer surfaces or the rubber components.
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