Oil Coming Out Of Breather Tube: Why It Is And How To Fix It

In a vehicle, there is an engine, and there is moisture. Now, the engine and the moisture do not mix. So for you to keep your engine dependable and safe, it is vital to take away and remove those harmful water vapor and liquid water. 

This is why we have the oil breather tube. This is the reason why the oil breather tube is made and designed to be in a vehicle. An oil breather tube is a section of plastic or even metal tubing, and they are from the engine and will vent into the outside. 

So you should know the importance of an oil breather tube. This oil breather tube is really low maintenance, and many drivers are not familiar with this component. You will not require a lot of time and effort in maintaining this breather tube, but it can encounter some problems. 

If your breather is blocked, it will pressure the engine, and it will cause failures in seals. The seals are held in oil. Without these seals, the engine will spurt the black stuff in all places, and the ending can be a total shutdown of the engine. 

There are also problems that there is oil coming out of the breather tube. Some drivers might have already experienced this, but for those who still have not, this article will help you get through the problem of having an oil out of your breather. Let us get started.

Oil Coming Out Of Breather Tube

Why Is Oil Coming Out Of My Breather Tube?

Drivers might have already experienced this issue. Some drivers would experience that there is oil leaking out of your breather tube. Now, there are few possible reasons why oil would leak out of your breather tube. 

First, your engine must have been overfilled with oil. So if you find that there is oil coming out of your breather tube, you must check if you have overfilled your engine with oil. Another thing that you must look out for is if your engine blowby is excessive. 

If your rings are not properly sealed and the combustion pressure will then reach the crankcase, it will chase and force the oil of your breather pipe. You can do a compression test. You can also do a leak down to confirm if this is the reason your oil is coming out of your breather tube. 

There can also be an assembly problem with your cylinder, piston, and your ing assembly. You must also check if your rings are correctly installed. Finally, if you have excess oil in your engine, it will create foam in your oil. 

This will also be blown out into your breather and will feed into the air filter. What you can do is disconnect the breather hose if you can. Then, push the breather hose into a tall bottle with a narrow throat, like a coke bottle. 

After that, start your engine for about ten minutes. After running the engine and seeing oil that is being blown in, recheck your engine oil level. You can also follow your owner’s manual for any instruction. 

If you also notice that your oil level is low or average, oil leaks out of your valves. So, in general, you can just check your clogged PCV system. 

There can be excess pressure on your crankcase, and there can be ring blowby that is too great. There can also be some sludge.

How To Stop Oil Coming Out Of The Breather Tube?

If there is oil coming out of your breather tube, then there can be excess oil in your engine. You must make sure that the oil in your vehicle is just enough. If you have excess oil in your engine, it can create some foam, and this foam will be then blown out into the breather and will feed on the air filter. 

So if you want to stop the oil coming out of your breather tube, you can take away the breather hose and disconnect it. Put the breather hose in a tall bottle and make sure that the bottle has a narrow and slim throat. Then, run your engine for about ten minutes and check if there is oil being blown in. 

The general rule would be to know the cause of the oil leakage from your breather tube first. There can be a few possible reasons. By identifying the problem, you will then know what the solution is. 

If the cause is that there is excess oil in your engine, you can take off some of that excess oil so that the oil will not be leaking out of your breather tube anymore. So the first thing you can do is to know what is the cause of the oil leakage. From then, you will then be able to know the solution.

Do You Need To Replace The Breather Tube Completely?

It is not very necessary to do this. If there is oil coming out of your breather tube, it does not automatically mean that there is a problem with your breather tube, and you have to replace your breather tube immediately. There is oil coming out of your breather tube if you have pressure in your crankcase. 

This means that you have pressure leaking past your piston rings. If you have a new and turbo engine, you can run your boost pressure higher so that you can get the horsepower out of your engine. 

You can also have your piston rings be on one hundred percent. So take your oil filler cap off and keep your engine running and notice if you can feel a difference in the pressure between the two engines.

Oil in Breather Tube

What Is The Best Prevention Of This Problem?

You must make sure that you are putting the right and enough amount of oil in your engine. Any excess oil can lead to leakage in your breather tube. 

You must also check your blow by now and then. If you have checked everything, then it must be a problem with your engine or motor issue.


In summary, an oil breather tube is vital in your vehicle. Some drivers might not be aware of this. But the importance of an oil breather tube is crucial.  

The oil breather tube is not hard to take care of, but you can encounter some problems. One of the problems is the leakage of oil in the oil breather tube. 

There can be possible reasons. Find the cause and identify the solution.

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Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more