Bad PCV Valve Symptoms – How to Fix A Bad PCV Valve

If you are someone who doesn’t even know what a PCV valve is, don’t be surprised because, to be honest, not a lot of people do. Let us, first of all, tell you what a PCV valve is, and then we can get down to its working and the symptoms that you might experience if it is failing or is bad.

What is a PCV valve?

What is a PCV valve

PCV valve

PCV stands for Positive Crankcase Ventilation. It is located at the bottom of your vehicle’s engine, and its job is to hold the motor oil.

When the gases or the fuel is burned inside your car’s engine, the exhaust fume passes through this valve, and it might block it, which can lead to some serious problems.

Why do we need a PCV valve?

Why do we need a PCV valve

Importance of PCV valce

To know the importance of a PCV valve, it is important that you learn how it works and all the tasks that it does.

When the fuel inside the engine of your car is burned, it produces an excess amount of waste gases. These gases are vented out of the engine of the car via an exhaust system. But some of these harmful gases may make their way through the pistons into the crankcase of the car.

When this happens, the gases get diffused into the motor oil that is present in the crankcase, and in turn, they pollute the oil and cause it to become sludgy.

When this oil is then transferred to the engine to start the car, it can cause the parts of the engine or the valves to corrode, and it may even lead to clogging of the valve which stops the oil from reaching the necessary parts and causes trouble while starting and driving the car.

These waste gases exiting the engines of the car all the time used to comprise 70 % of unburned fuel, which causes air pollution and even contributes to global warming.

So to cater to the problem, since the year 1964, laws were passed to make sure that these harmful gases are not released into the air unchecked. This is where the PCV systems came in handy.

What does a PCV valve do?

What does a PCV valve do

PCV valve

PCV was initially installed inside the vehicles so that they would recycle the waste gases that the engine releases.

These gases are mixed up with the fuel and then resent to the car’s engine to be once again burned. The main job is to reduce the amount of gases that were being released into the air.

The PCV valve is a valve that only works one way and is attached to the crankcase. The waste gases can exit via the PCV valve, but they cannot reenter through it. This way, a PCV valve is able to filter them out and recycle them by re-forcing them into the fuel that is later served to the car’s engine.

Symptoms of a bad PCV valve:

To be able to solve the problem, the issue you first need to know where the issue lies, and for this, it is important to know if the PCV valve is causing the problem or not.

Once you are aware of whether it’s the PCV valve or not that is causing the issues with your car, you can get down to fixing it, and we will tell you how.

Here are some of the most common symptoms of a failing PCV valve:

1. Check engine light is turned on:

Check engine light is turned on

Engine light is turned on

The first and the foremost thing that you need to check is your check engine light. If it is turned on, it means that there is something wrong with the car.

A check engine light is designed to turn on and start flashing as soon as something goes wrong in the car and fails to do its job properly. You can make sure that the problem is with the PCV valve by scanning the Engine Control Unit (ECU) with an OBD2 scanner.

Run the codes that you find with the scanner and compare them to the ones of your vehicle, and you will know which part is causing the problem. You can also get your car scanned by a mechanic or at a garage.

If you don’t have an OBD2 scanner, which is likely but okay, then you can check for the following symptoms.

2. High oil consumption/ less efficiency:

As we explained earlier, if the PCV valve is blocked or clogged in any way, then the gases start forming pressure inside the crankcase, which then leads to oil leakage, etc. This also causes an increase in the consumption of oil in your car.

So if you observe either of the two, it is advisable to get your PCV valve checked and replaced as soon as you can.

3. Rough acceleration of the car:

Rough acceleration of the car

Rough acceleration

The contaminants that are formed in the car’s fuel due to a faulty PCV valve can lead to a rough acceleration in the car. This could be observed in both cases, when increasing speed and whilst reducing it.

4. Fault in the filters:

When the PCV valve is not able to do its job, it may result in other parts of the car getting clogged or contaminated with the waste gases.

One of these parts could be the filter. In most cases, when the PCV valve stops working, the filter gets clogged with oil and hydrocarbons.

This is mostly due to the fact that pressure is developed inside the crankcase, which leads to the waste gases and water vapors coming out of the breather element that is the filter.

This is another reason that causes an increase in oil consumption. So if you sense an increase in oil consumption and the filter is defective as well, know that the PCV valve has failed to do the work.

5. Different colors of smokes coming out from the exhaust of the car:

If the PCV valve stops working, it leads to contamination building up in the fuel. When this fuel is burned in the engine, it could lead to strange colored smoke coming out of the exhaust. The smoke could be blue or white or yellow.

In another case, if the PCV valve or the hoses are blocked, due to the pressure in the crankcase, it could lead to the oil being fed to the combustion chambers. Once the oil is burned in the combustion chamber, it could also lead to smoke coming out of the exhaust.

In either case, if you see smoke coming out the exhaust of the car and you generally don’t see it, then it is most probably because the PCV valve has stopped working.

6. Rough Idle or a High idle RPM

Rough Idle or a High idle RPM

Rough Idle or a High idle RPM

Now as you know that the PVC valve controls the air and the gases that flow between the crankcase and the manifold, in the case that the PCV valve is damaged, symptoms similar to an air leak can be observed.

This comes out in the form of either a rough idle, that is, the idle is behaving in a strange manner, or it could be that the idle RPM is too high. In these cases, it is obligatory to check the PCV valve because it might be damaged.

7. The air mixture becomes rich or lean:

If the PCV valve is damaged, it is not properly able to filter the air and due to this reason the air will become contaminated with waste gases and the air leak, as we discussed in the above heading, maybe rick with waste gases and come out in the form of a lean mixture of sorts.

8. Misfires in the cylinders:

Now, as we discussed in the above two points, a faulty PCV valve can first lead to high or a rough idle, and then it may even lead to a rich or a lean mixture, which causes an air leak.

Now, this lean mixture can also result in misfires in both the case of acceleration or in the idle.

This is due to the fact that the air in the cylinders gets contaminated, and due to the pressure that builds up because of it, it may lead to misfires in the cylinders. A rich mixture while burning can also cause sparks and result in misfires.

9. Strange hissing noise coming out of the engine the car:

Strange hissing noise coming out of the engine the car

Hissing noise from engine

If the problem is due to the PCV valve leaking, then the leak causes a strange hissing noise that is produced in the engine.

As discussed under the above few headings, this may lead to air contamination, which results in misfires and, in some cases, explosions. So it is important to fix it as soon as possible.

10. Poor efficiency:

With the PCV valve not working properly or as it is supposed to be, the air is not being filtered. This causes smoke to come out of the exhaust, or increase in the oil consumption, or a hissing noise in the car’s engine. All in all, it results in poor efficiency of the vehicle.

It consumes more fuel and gives less mileage and even causes oil and air leaks and should be looked at.

How to fix a bad PCV valve:

How to fix a bad PCV valve

Bad PCV valve

Once you have diagnosed the symptoms and reached the conclusion that the PCV valve is damaged and needs to be repaired or replaced, you will need to know-how.
So under this heading, we shall discuss two methods. It may be that your car’s PCV valve only needs to be cleaned as it might be clogged or blocked.

In that case, we will teach you how to clean the valve, and in the second case, it may be that your PCV valve is permanently damaged and has reached the end of its lifespan and needs to be replaced. In that case, we will teach you how to located and replace a PCV valve.

1. How to clean a clogged PCV valve:

How to clean a clogged PCV valve

Clogged PCV valve

a. Firstly determine the location of your PCV valve. It varies from car to car, but mostly it is located near the or on the manifold. If you can’t find it there, check out your vehicle’s manual. With that, you will be able to determine the location of the PCV valve.

b. A cylindrical shaped hose is mostly used to cover the valve. First, carefully remove the hose and then the PCV valve with the help of pliers. Pull the valve straight up, and it should detach. Now put it down on a rag.

c. Now you have to clean the PCV valve. For that all you have to do is use an engine degreaser, you should be able to get all the oil out with the help of a degreaser from inside and outside the valve. You can also try cleaning it with the help of an air compressor to dry the degreaser.

d. The last step is to reattach the PCV valve in its place. This is easy; simply wrap the PCV valve in the rag and then, with the help of pliers, gently put it in place. Don’t press yet. Attach the rubber hose and then push the valve back into its place.

2. How to Replace the PCV valve:

If you know how to detach, clean, and reattach the PCV valve in its place, then replacing it shouldn’t be a problem. Follow the below-given instructions, and you will be good to go:

a. Locate the PCV valve in the car with a manual or by looking at your car’s manual.

b. Remove the hose and then the valve.

c. If you find that the hose is dry or full of sludge or has any other hard deposit, then you should replace it as well. If the clamps holding the valve in place are rusty, replace them too.

d. You already know how to reattach the valve. Put the valve back in its place and then the hose with the help of a set of pliers and press it back into its place.

e. Start the engine and check for any leaks in the PCV valve to make sure you have properly placed it.

How does a PCV valve gets damaged?

How does a PCV valve gets damaged

PCV valve gets damaged

The waste gases, when leaving through the valve, might corrode it eventually; therefore, it is necessary to replace it or clean it every now and then.

The valve itself is inexpensive and can be easily replaced, but if not replaced in time, it can cause serious damage to the engine and might cost you a lot more.

Why is it important to regularly clean and maintain the valve and replace it in time?

Now, as you know that the PCV valve makes sure that the excess amount of gases leaves the crankcase, but if it’s not properly working, at high speeds, the engine of the car might be working so hard.

And could produce a lot more excess gases which could lead up to a pressure building in the crankcase and might even cause an explosion or heating up, which could lead to leaks and cause damage to the seals.

The average lifespan of a PCV valve and after how long should it be replaced:

The average lifespan of a PCV valve and after how long should it be replaced

Average lifespan of a PCV valve

A PCV valve does not have a defined lifespan. It mostly varies depending upon factors such as how often did you clean it and whether you changed the oil regularly or not etc. If you keep these factors in mind, you might be able to extend the lifespan of the PCV valve.

On average, you are supposed to change it at least at every major service of the car, but it is likely that it may need replacement earlier than the scheduled service.
Why is it significant to replace the PCV valve timely?

If the PCV valve is corroded and not working properly, it may lead to contamination in the car’s engine. This could reduce the car’s efficiency and also causes higher fuel consumption.

A faulty PCV can also result in sludge building up in the tank, which could lead to blockage. The pressure of the gases can lead to an explosion. This explosion might result in damaging other parts of the car.

A faulty PCV valve also causes contamination in the fuel, which leads to higher oil consumption and, thus, a decrease in the efficiency of the vehicle.

In short, if you don’t timely replace the valve, it may cost you a lot of repair costs due to its consequences.

Final Thoughts:

We have discussed what a PCV valve is, what it does, why it’s significant, and what are the symptoms of a bad or a failing PCV valve.

Once you know that the PCV valve is failing, you need to know how to fix it. For that, you have two options. One is to replace it, and the other is to repair it.

It is important to remember that even though a bad PCV valve may not refrain the car from starting but it is still an urgent matter as it can lead to other problems if not dealt with in time.

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