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How to Fix Oil on Spark Plug Threads in 5 Easy Steps

how to fix oil on spark plug threads

Spark plugs are an essential part of your car’s engine that helps start the ignition of your vehicle. However, since it’s located in the depths of the valve, it is susceptible to a lot of problems.

Spark plugs tend to have misalignments as well as inaccurate gaps. However, you may also encounter oil on spark plug threads which can be a serious problem. With this issue, you might ask, what causes oil on spark plug threads?

Why does my car’s spark plug threads have oil?

Because a spark plug is tasked with the engine’s ignition, it needs to be in full contact with the output terminal of the ignition coil. It delivers the “spark” which then fires the air-fuel mixture in the engine for it to work properly.

As we all know, oil is not a good electric conductor. So if the spark plugs are drenched in oil, the spark won’t be delivered. Thus, spark plugs with oil on their threads usually cause the engine to misfire. It’s one of the main symptoms of a faulty spark plug.

However, it’s important to note that your spark plug is not at fault here. There’s no oil inside the spark plug, and neither does it produce one. Instead, it’s highly possible that the main culprit here is the gaskets.

What You’ll Need

  • Socket and spark plug socket
  • Screwdriver
  • Valve cover gasket and O-ring spark plug tube seal
  • Engine sealer
  • Power Handle
  • Pliers
  • Ratchet and extension
  • Spray cleaner (for oil)

Step 1. Understanding the gaskets

Many car owners tend to overlook the gaskets since it’s a small piece in the engine. However, it’s as important as any of its parts. If you’re a novice to the engine’s construction, always remember that gaskets are meant to seal.

These are usually the elastic bands that are attached to a particular component of the engine. Gaskets vary and are usually shaped into the component it seals. An example of this is cylinder gaskets, head gaskets, and the valve gaskets.

A faulty gasket will allow oil and other engine fluids to seep in wherever it wants freely. Thus, a broken valve gasket is the reason why spark plug threads are covered in oil.

Step 2. Remove the valve cover and the spark plugs

the internals of the engine under the valve cover

To get to the cause, we’ll need to remove the valve cover because it stores the spark plug tubes. Before this, be sure to remove the spark plugs one by one using a spark plug socket and ratchet.

Once you removed all of it, start removing the clamp connecting the valve cover to a hose. You can simply do this by using a pair of pliers to unlock it. Afterward, use your hands to pry out the hose.

Next, remove the harness that lies across the valve cover. Once you’re through, you can now use a power handle and socket to unscrew the nuts on top of the valve cover. Unscrew it one by one until it’s easy to remove it with your fingers.

Finally, get a flat screwdriver and stick it in the valve cover’s gap. This helps you pry out the cover since it is tightly secured. After you loosened it, gently lift it up and set it aside.

Step 3. Removing the seals

After you removed the valve cover, you’ll notice the seals located in each spark plug well. These are the ones that fail to protect the spark plug from the oil. Replacing these are easy, so be sure to have newly bought seals and valve cover gasket.

Although the valve gasket might not be at fault, it’s better to be on the safe side and replace it as well. Many manufacturers sell spark plug seals with valve cover gaskets, so it’s a lot more convenient too.

Step 4. Installing the valve cover gasket

gasket car engine valve cover

Start by installing the valve cover gasket. This gasket is uniformly shaped towards the cover, so all you need to do is secure it tightly around the edges. To make things easier, add a liquid sealer on the edges before placing the new gasket. This prevents the gasket from slipping.

A good tip when buying the best gaskets is to look at its material. Usually, long-lasting gaskets are made out of high-quality silicone. These types often don’t need retyping which reduces your work.

Step 5. Installing the spark plug well gasket

The next step is to place the spark plug gaskets. These are circular gaskets that lay on the rim of the spark plug well. Similar to the valve cover gasket, add liquid sealant around its inner circle.

Afterward, place it on the spark plug well and push it down tightly. After securing it in place, you can proceed to add the nuts that we previously removed a while ago. Spin it with your hands until it sets, then gets the power handle and socket to lock it in place.

When tightening the nuts, be sure to follow the correct way to avoid damaging your valve cover. Starting from your left, you’ll see valves 1,2,3 and 4. Tighten the nuts with an order of 2-3-1-4.

Once you’re done tightening the nuts, all that’s left to do is to put everything back in place. Connect the hoses, the wiring harness, and the spark plug wires. Should your engine have a lot of oil splatters, you can rinse it off by spraying an oil cleaner.

Wrapping it Up

Spark plugs may be small, but its role in the engine is as big and important as the entire cylinder. Thus, it’s part of a car owner’s responsibility to check the condition of the spark plug always. Remember, an oily spark plug is just one of the many problems of this component.

Fortunately, spark plugs having oil on the threads is an easy fix. The gaskets are cheap, and the workload is minimal. Just be sure you have all the right tools. Furthermore, it’s important to focus especially when you’re unscrewing and tightening the valve cover.

So there you have it, oil on spark plug threads is something that you can do in your garage. There’s no need to spend a fortune for a car repair. If you found this article informative, leave a comment below and share this with your fellow friends! Good luck!