How to Stop Oil Coming Out Of Valve Cover Breather?

Oil leaking out of the valve cover breather can harm your car’s engine if not checked and fixed as soon as possible. Meanwhile, you will experience several malfunctions if your vehicle’s engine is compromised.

Therefore, understanding how to stop oil coming out of valve cover breather will save you from a lot of engine trouble. However, before we delve into fixing the oil leakage problem, let’s see why oil blows out of your car’s valve cover breather.

Thereafter, you can be sure of fixing the problem once and for all with the recommendations provided in this article.

oil coming out of valve cover breather

What Causes Oil to Blowing Out Of Valve Cover Breather?

You may experience oil blowing out of your vehicle’s valve cover breather for various reasons.

Identifying the actual cause of this challenge in your car is the first step to fixing the problem. Therefore, let’s see some of the common causes of valve cover breather leaking oil.

Excessive oil in the crankcase

Excessive oil is one of the foremost causes of oil coming out of valve cover breather. Having excessive engine oil in your car will eventually cause the fluid to foam and leak out through the breather.

While running your engine on a low oil level is not advisable, it is also not ideal for topping off the lubricant beyond the designated maximum level. This is because of the consequence of having oil in valve cover among other effects.

Damaged oil seals

Damaged or worn-out oil seals are another culprit to oil leaking from valve cover breather. The worn-out seals allow pressure leakage, allowing oil to go down into your car’s inlet passage.

Damaged compression rings

Damaged or faulty compression rings can also be why you’re experiencing oil blowing out through your car’s crankcase breather. Defective rings will allow compression to leak out, thereby pressurizing the crankcase and pushing more oil through the breather.

Meanwhile, you will most likely have oil getting into the combustion chamber when the rings and valve guides are loose. You can also notice smoke coming from oil cap due to the issue.

High pressure on the breather.

High crankcase pressure is yet another cause of oil coming out of crankcase breather. Meanwhile, leaking cylinder gaskets, broken piston rings, and worn cylinder bores are common reasons for high crankcase pressure, which further results in oil blow-by.

Blocked valve

Finally, a clogged or blocked PCV valve can also be responsible for oil blow-by through the crankcase breather.

Therefore, if you’re asking, “Why is oil coming out of my breather?” one or more of the causes stated above may be responsible for the problem.

So, pay attention to the particular cause of the valve leaking oil to figure out the most appropriate solution to implement. Let’s see how to fix the problems that have been outlined above in the next section below.

How to Stop Oil Coming Out Of Valve Cover Breather

Fixing oil coming out of PCV valve is straightforward when you are able to identify the actual cause of the problem. Nevertheless, the following recommendations can help you rectify the issue.

Oil Coming Out of Valve Cover Breather YouTube

Remove excess oil from the engine

If you have too much oil in the crankcase, drain out the extra oil. You only need to get underneath the vehicle and drain the excess oil.

To do this, locate the drain plug underneath the vehicle and loosen it to drain out the excess oil. Meanwhile, ensure to put a pan underneath to catch the oil and dispose of the fluid appropriately. 

Replace damaged oil seals

Damaged oil seals have no use in the system. They will continue to pose a challenge as long as they remain. So, ensure to replace them once you notice that this is the cause of oil blowing out from your vehicle’s crankcase breather.

Replace damaged compression rings

Ensure your compression rings are in good shape at all times. Always replace them when overhauling the engine. Most car models require you to replace the compression rings whenever you remove the pistons whether they are good or not.

Again, if you notice that broken piston rings or a leaking cylinder gasket are responsible for the oil blow-by through your breather, ensure to replace them as well.

Replace damaged PCV valve

Lastly, if the PCV valve is damaged, ensure to replace the component also. Replacing a PCV valve costs around $50 – $250. Parts cost around $20 – $50, while labor costs about $30 – $200, depending on the vehicle type and the auto mechanic’s shop or location.

Is An Oil Leak From A Valve Cover Serious?

Of course, an oil leak from a valve cover must be taken seriously due to its consequence. Allowing the leaks without any inspection or rectification can cause your engine to run out of oil, which can cause vibration and even catastrophic damage.

Meanwhile, engine damage can be very costly to fix. Whether or not you’re buying a new engine, the cost can significantly impact your pocket.

Therefore, if you experience a leak from your car’s valve cover, ensure to inspect the situation or contact an expert auto technician to fix the problem ASAP to avoid escalations.

Can I Drive With Valve Cover Leak?

Even though it is possible to drive with a valve cover leak, it is not advisable to do so because of the risk you may be exposing your car to in the long run. Driving with a valve cover leak can trigger overheating when you least expect.

While it is possible to drive in this situation, it would be best to immediately contact a professional auto mechanic to diagnose and fix the issue. Allowing this kind of situation to linger for too long can gradually damage your car’s engine.

It is important to state that responding swiftly to faulty components is another way to make your car last longer besides regular maintenance. It would be best if you made it a habit to swiftly respond to faults within your vehicle whenever they arise.


If you were wondering how to stop oil coming out of valve cover breather in your car, this article has justified your contemplation. However, ensure to first inspect the situation to identify the exact cause of the oil blow-by to match it with the exact solution.

While some repairs can be relatively easy, especially for DIYers, it is vital to know where to draw the line and contact a professional auto mechanic for more complicated repair issues.

Finally, developing a routine maintenance habit can help you avoid unnecessary vehicle faults or damage. Therefore, you may want to resolve to keep to your car’s routine maintenance as often as possible.


Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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