Oil on Spark Plug? Try these Fixes

Having oil on your spark plug shows that there’s probably a leakage that needs immediate attention.

Although it isn’t as harmful as the Limp Mode issue, it’s necessary that you address it on time before it escalated.

As well known, oil and lubricant are meant for the engines, pistons, and other moving parts to reduce the effect of friction.

But if you notice oil on your spark plug thread while servicing your vehicle then you shouldn’t panic as I’m going to offer you a solution to it.

What Does Oil on Spark Plug Mean?

Although, oil deposits don’t just come up on your spark plugs like that, when there’s one, it implies that there must have been a breakage or leakage somewhere in the engine.

Continue reading to learn what to do if you see oil on your Spark Plug thread or tip.

What Causes Oil on Spark Plug/Spark Plug Thread

Highlighted below are some of the major reasons why oil will leak into your spark plugs 🔌

  1. Pouring Excess Oil
  2. Faulty O-Rings
  3. Defective Piston
  4. Bad Valve cover gasket
  5. Problematic head gasket
  6. Faulty Valve Guides
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Excess input of oil into your car engine will definitely cause an overflow which will likely deposit oil into your spark plug. Also, if the oil is dirty then it’ll spread dirt into the spark plug making you experience difficulty In starting your vehicle.

Similarly, the O-rings which are often attached to the valve cover help prevent oil leakage into the spark plug. So, any breakage in the ring due to wear and tear will lead to the free flow of oil into the spark plugs.

Also, a cracked Piston can cause oil spillage into the spark plug when there are one or more cracks on it.

Finally, if the valves and gaskets which help in alignment and sealing break or become defective, there’ll be severe leaks that will eventually get to your spark plugs.

What to do if there’s oil on your Spark Plug?

If you find oil in your spark plugs it’s required that you clean them to clear any dirt or debris that might affect your vehicle performance.

Here’s a guide on how to clean your spark plug thread

  1. Loose and clean the Spark Plug(s)
  2. Clean the hole where the spark plug is attached with a neat cloth or a carburetor cleaner
  3. Reinstate the cleansed spark plug(s) into its hole

Your spark plug should now have a new look and extra lifespan added to it.

However, if you notice frequent oil deposits in your spark plugs then follow the below guide to permanently stop it.

How to Stop Oil Deposit on Spark Plug Threads

The first step toward fixing oil on Spark Plug Threads is by finding out the root cause of the leakage.

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It could be from an over-oil filling, a defective Piston, the O-rings, or any of the valves.

Whichever one it might be; here are some fixes you might try to stop oil deposit on the Spark Plug.

1. Drain Extra Oil

If you notice oil flows into your spark plug as a result of excess input of oil then you can go ahead to drain some amount by opening the drain plug.

This will allow excess oil to flow out of the engine. Alternatively, you can use an oil extraction pump for this purpose.

2. Install new O-Rings

If any of the O-rings on your valve cover has worn out then you should consider getting a replacement as soon as possible.

You can now proceed to install the new O-rings by removing the valve cover, removing the previous rings, and installing oiled O-rings as a replacement.

Also, do well to ensure the new O-rings fit properly and their tapers are faced directly towards the engine.

3. Head Gasket Replacement

It’s advisable to take your vehicle to a mechanic to replace your head gasket. Also, you can decide to make the purchase and take it to an auto shop for a fix.

4. Change Defective Piston

Also, this will require the attention of a professional automotive engineer. Kindly take your car to your mechanic shop and ask them to change your Poston.

5. Valve Cover Gasket Replacement

You can purchase a new Valve cover gasket in any auto aftermarket close to you and initiate a replacement yourself.

However, you should perform the operation with caution to avoid leaks.

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That’s it.

Does Small Amount of Oil on Spark Plug Threads Matter?

No, you don’t have to worry about it but the accumulation of too much oil in your spark plug might introduce debris and dirt which isn’t healthy for your vehicle.


We’ve discussed possible reasons why there could be oil deposits in your spark plug with its corresponding solutions.

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