Why Are My Spark Plugs Wet with Oil?

The proper performance of spark plug is highly important. As you know the plugs in the car are responsible to ignite electricity so that the fuel and air mixture put forth the combustion process.

So when they are worn out you certainly need to replace them with the ignition ideal. But sometimes you see the spark plugs covered in oil. So any car owner can wonder why my car spark plugs wet with oil.  

Over the course of time, the spark plugs can get contaminated with oil. The reason can be leakage in the component, or some issues with the car engine itself. Therefore, the spark plug covered in the oil layer won’t be able to ignite the spark and the engine can misfire.

So in this post, we shall look deeper into the matter and find out the reasons, symptoms, and the solution, for sure.

Common Reasons of Oil on Spark Plugs

Here are the common reasons that cause the spark plugs to become wet in oil.

  • Smell of Gas from Exhaust: If you smell pungent and strong gas from the exhaust the reason can be spark plugs are covered in oil. This is because the cold fuel is hard to vaporize therefore more fuel is needed to make fuel combustion of fuel a practice
  • Increased Fuel Consumption: When the fuel consumption is enhanced, the oil consumption gets high for the very reasons. This can make the spark plug we oil. The reason can be non-reliable spark plugs so that the engine doesn’t underperform.
  • Blue Smoke from Tailpipe: The most common reason why you see oil wet spark plug is when there is blue smoke tailpipe. The engine oil of the spark plug doesn’t let the spark to ignite and increases the air fuel in the cylinders.
  • Decreased Engine Performance:  The fuel air mixture in the cylinders is not a good sign for spark plugs. Therefore, the result is the acceleration lagging and hence engine performance gets poor.
  • Engine Misfire/backfire: When the engine backfires or misfires it can promote the issue such as spark plug in the oil cover. Engine misfire is when there is incomplete combustion inside one of the engine cylinders. And that can be due to oily spark plugs. Whereas when the fuel-air mixture doesn’t burn the right way, it’s because the oil deposits in on the spark plugs.

Now let’s find out why spark plugs get oil!

Why Are My Spark Plugs Wet with Oil

Leaky O-Ring Seal

The leakage is the one major reason why the spark plugs are covered in oil. If the O-rings/spark plug tube seal is leaky, it means that there is oil on them for sure. The seal is to keep the engine oil and coolant on the side, and if that is broken/defective things become compromised.

Worn Out Intake Valve Seals

Intake valves regulate air and fuel inflow while controlling exhaust outflow. If their valve seals wear out, motor oil can enter the crankcase combustion chamber and cause oil fouling in your spark plug well.

Blown Head Gasket

In vehicles, the head gasket is in the middle of the piston head and engine block that keeps the oil from becoming contaminated. When the motor oil makes its way in the combustion chamber it means you have blown the head gasket. This motor oil can leak in the plug wells and on the spark plug threads.

Faulty Piston Compression Rings

Another reason is when the piston compression rings are bad. The piston compression rings seal the small space between the piston and the cylinder wall. So the space is vulnerable to accumulation of excess engine oil from the cylinders wall.

If the piston rings are worn-out can promote wear and  tear it can also cause oil leak in the spark plug hole.

Bad Plug Well Grommets

Anything bad in the engine and around it will impact the performance in many ways. So if your car engine gas the dedicated grommet to keep off oil from passing through the plug make sure it works well too. In case these grommets are defective due to durability, there can be oil in the spark plugs.


Is there any way to fix oil on the spark plug?

Is there any way to fix oil on the spark plug

Before processing, it’s important to find out the real problem with the spark plug. If the plugs are worn out there is nothing much to do about except to replace them. However, for quick fixing of oil o the spark plug:

  • Turn of the car engine and disconnect the battery and remove the valve cover
  • Look for the spark plug wire or coil pack and take out the bad spark plug and spark plug boot using a spark plug socket.
  • Take out the old gasket seam from the cylinder and clear the traces that are left behind.
  • Clean the cylinder head and valve cover with degreaser and also each spark plug and its tip with carb cleaner spray.
  • Now install a new plug using spark plug socket, new gasket and O-rings and put back the cover and. Don’t forget to reconnect your battery.

Can I drive with oil on spark plugs?

Although you can drive if oil is on the spark plugs, it’s not an ideally recommended way. The engine oil on the spark plugs means the electrodes will not let the spark to ignite them. If you keep on driving with oil on spark, you may end up with costly repairs.


It’s never recommended to drive the car without proper maintenance. If you do find the odd car performance in any way you should keep up with its regular maintenance.

Spark plugs being the most important component for car ignition demand to be cleaned, checked, and replaced if needed. Hopefully, this article has helped in knowing the reasons and solution for oil on spark plugs.

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