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Can You Use Dielectric Grease on Spark Plugs?

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Spark plugs can clog up with carbon and other deposits. As a result, one may need to change them with a new set. Nonetheless, some car owners tend to apply an oil or lubricant coating to prevent corrosion. 

Most people go for dielectric grease. However, since this product isn’t designed for plugs: can you use dielectric grease on spark plugs?

Can you use Dielectric Grease on Spark Plugs?

Can you use Dielectric Grease on Spark Plugs

Yes, you can.

Dielectric grease is a synthetic lubricant used for electrical connections. It forms a waterproof coat that prevents electrical cords – like spark plugs – from corrosion, making them last longer.  

Dielectric grease also improves materials’ electric insulation properties, ensuring that charges remain within their boundaries. You can use it on almost any spark plug, wire, or terminal assembly.

What are the Best Dielectric Greases for Spark Plugs?

What are the Best Dielectric Greases for Spark Plugs

There are two main types of dielectric grease: 

  • Petroleum-based
  • Silicone-based

Both have different properties that make them suitable for various applications.

You can apply petroleum-based grease on any metal surface without compromising its performance. However, it may degrade over time if exposed to sunlight or excessive heat: This means it can become ineffective at preventing corrosion if left in one place for too long.

Silicone-based grease lasts much longer than petroleum-based grease. However, it takes longer to dry out when exposed to moisture.

If you’re looking for the best dielectric grease for spark plugs, here are four excellent options:

Permatex 22058 Dielectric Tune-Up Grease, 3 oz. Tube

Loctite 495549 Dielectric Tune-Up Grease Tube, 80-Milliliter

CRC Industries, Inc. 05109 Dielectric Grease .5Oz Tube, White

Mission Automotive 4 Oz Brush-On Oil-Based Battery Corrosion Preventative

What to Do If There’s Too Much Dielectric Grease on Spark Plugs

What to do if There's Too Much Dielectric Grease on Spark Plugs

If your spark plugs are difficult to remove, you may have used too much dielectric grease on the threads. You should use just enough to keep the electrode from shorting out against the cylinder head: But not so much that it prevents the plug from coming out effortlessly.

You can use a torque wrench to check for excessive torque. However, it’s better to use your finger as a gauge.

If it’s hard to turn, unscrew it and apply dielectric grease. If it still feels tight, try with more dielectric grease before giving up. 

Your last resort is removing the old spark plugs with a pipe or ratchet wrench.

Why You Should Avoid Too Much Dielectric Grease on Spark Plugs

Why you should avoid too much dielectric grease on spark plugs
  1. Can cause misfires

Too much dielectric grease can cause misfires because there’s no room for airflow around the spark plug wire. It may also cause fouled plugs due to carbon buildup around the threads.

  1. May leak into your engine’s oil system

Too much dielectric grease might stick to the spark plug threads. And, whenever you tighten the spark plug, it will squeeze out and get into your engine oil system. This leakage can damage your engine over time by creating sludge in the oil filter. It can also clog up your engine’s internal passages by building up in them. 

  1. May enter the combustion chamber 

If dielectric grease seeps into your engine block, it might reach the combustion chamber.

During combustion, this grease burns off along with fuel, which isn’t suitable for emissions. 

It may also cause more wear on pistons due to increased friction when this material burns off within the chamber.

Possible Downsides of Using Dielectric Grease

Possible Downsides of Using Dielectric Grease

There are a few disadvantages to using dielectric grease on spark plugs. 

First, this grease’s primary role is to fill gaps, rather than lubricate them. Therefore, it may not provide any lubrication when it comes to contact with hot metal surfaces within the engine — and may damage it.

Furthermore, dielectric grease is tough to remove once applied. If you use too much dielectric grease, you may not be able to remove the spark plug without damaging it, or the cylinder head.

You can consider a regular lubricant instead of dielectric grease if you want to apply something to the plugs.

Still, you can use dielectric grease on your spark plugs if you want. What might happen is that the grease will melt due to the higher temperatures near your spark plugs. The melted grease won’t cause any damage, but it might make things look messy around your spark plugs whenever it starts leaking out.

When Should You Not Use Dielectric Grease?

When Should You Not Use Dielectric Grease

Dielectric grease is a fantastic way to protect your electrical connections from the elements. This type of grease has excellent electrical properties and can withstand fairly high temperatures. It’s also easy to apply and remove, which makes it ideal for use in many different applications.

However, there are some instances when you shouldn’t use dielectric grease: 

  •  If your connection is already waterproof 

If there’s no way for water to tamper with the connection, then there’s no need to apply dielectric grease on top of it.

  • If parts of your connection get hot enough to spark up the silicone oil

Avoid dielectric grease if portions of the linking get hot enough to spark up the silicone oil. Dielectric grease is flammable above 300°F (149°C) and can emit toxic fumes at high temperatures.

Do Coils on Plugs Need Dielectric Grease?

Do Coils on Plugs Need Dielectric Grease

No. Plugs don’t need dielectric grease. Nevertheless, your plugs can benefit from greasing. This greasing is especially proper if you submerge your car in water or drive in harsh environments.

Dielectric grease protects the spark plug and its threads from corrosion. It also reduces wear, improves heat transfer, and helps prevent electrical shorts.

You can use it on any spark plug before inserting it into your engine block and any plug terminal that moisture may tamper with eventually. 

Where Do You Put Dielectric Grease on Spark Plugs?

Where Do You Put Dielectric Grease on Spark Plugs

You can put it on the threads at the top of the plug. Also, it meets the engine block around the bottom of the spark plug. This application will help prevent corrosion from occurring between these two surfaces. The best way to apply it is by dabbing it onto the metal connectors with a cotton swab. Also, remember to use just enough grease and smear it evenly on the metal surface.

You should never submerge wires in it or allow excess grease into the spark plug hole – you’ll only end up with a messy mess!

Final Words

Dielectric grease is not a must. Nonetheless, you can apply it on spark plugs if you like. If you choose to use it, make sure you don’t apply too much of it. A thin layer should do just fine. 

Remember, too much grease leaves a residue over time. This can cause corrosion to the metal inside the plug, leading to possible misfires.

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