Can You Put Dielectric Grease on Spark Plugs?
You can buy a bottle of dielectric grease for less than $10 to insulate and protect your spark plugs from dirt and corrosion.
Written by Andrew Biro
Edited by Pat Roache
Dielectric grease is a non-conductive silicone lubricant that can be applied to the inside of a spark plug’s rubber boot to better insulate it and protect it from moisture and leakage.
- Dielectric grease is an inexpensive tune-up grease (less than $10 for a 3 oz. tube) used to seal and protect electrical connections—like spark plugs!
- Dielectric grease helps your spark plugs last up to 100,000 miles by deterring arcing and preventing the rubber boot from bonding to the spark plug’s ceramic portion.
- A small quantity of dielectric grease should be applied directly to the rubber spark plug boot to properly protect the plug.
- Dielectric grease is an inexpensive tune-up grease (less than $10 for a 3 oz. tube) used to seal and protect electrical connections—like spark plugs!
- Dielectric grease helps your spark plugs last up to 100,000 miles by deterring arcing and preventing the rubber boot from bonding to the spark plug’s ceramic portion.
- A small quantity of dielectric grease should be applied directly to the rubber spark plug boot to properly protect the plug.
Dielectric grease extends your spark plug’s lifespan
Dielectric grease is a waterproof, non-conductive substance commonly used in automotive tune-ups to seal and protect high-voltage electrical connectors from dirt and corrosion.
How much it costs: Dielectric grease is incredibly affordable. For example, you can get a three-ounce bottle of
Permatex dielectric grease on Amazon
for less than $10!Most dielectric greases use a combination of silicone and thickener, such as polydimethylsiloxane. It has the following advantages when applied to spark plugs, gasket rings, distributor caps, and more:
- Insulates against moisture and other contaminants
- Prevents corrosion
- Deters electrical arcing and voltage leakage
- Keeps rubber components from drying out, cracking, or bonding to ceramic portions of electrical components
- Extends electrical components’ lifespans, reducing their replacement frequency
Spark plug life expectancy: Spark plugs are expected to last 80,000 to 100,000 miles with the proper maintenance. Dielectric grease ensures that your
spark plugs
reach this life expectancy and, in some cases, surpass it!How to put dielectric grease on spark plugs
Follow the DIY instructions below to apply dielectric grease to your spark plugs:
- Remove the spark plug and clean both the plug and rubber boot.
- Squeeze a small dab of the lubricant onto a cotton swab.
- Insert the swab into the spark plug boot.
- Use a circular motion to apply a thin coat of dielectric grease to the interior of the boot. Keep even pressure as you go.
- Be careful not to get any of the silicone grease on the metal terminal(s).
- Reinstall the plug boot and spark plug.
Dielectric grease only needs to be applied to the rubber boot where the spark plug meets the ignition coil. Keep the following tips in mind:
- Dielectric grease is non-conductive, meaning it should never be applied directly to spark plug wire terminals or electrical joining surfaces like sockets.
- Too much dielectric grease can form a barrier between mechanical connections, thereby reducing their conductivity and potentially causing anengine misfire.
Expert tip: If you want to go the extra mile, you can also apply a thin coat of dielectric grease to the exterior of the spark plug’s ceramic insulator. As long as you don’t get any of the grease on the electrical conductors, it provides an extra layer of protection.
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FAQ
Is dielectric grease necessary for spark plugs?
While it’s not strictly necessary—you won’t cause your vehicle to malfunction by failing to put dielectric grease on your spark plugs—it can help to extend the lifespan of these crucial components of your car’s ignition system.
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