Car Engine E1609805546252

PCV Valve Symptoms, Location & Replacement Cost

In Engine by 10 Comments

You have probably heard about the PCV valve before in a gas/petrol engine. But you probably didn’t know how important this little part is to the engine. This little piece is a widespread problem, and the problem occurs in almost all different petrol engine manufacturers.

Most of the PCV valves are made of plastic hoses with a spring inside. As you can imagine, any plastic would wear out after 10 years, fitted in a hot place like the engine bay, and because of the importance of the PCV valve; you will get a lot of different symptoms from it when it fails.

In this article, you will learn everything you need to know about the PCV valve. Let’s begin with the symptoms of a bad PCV valve.

Top 7 Bad PCV Valve Symptoms

As you now know that the PCV valve is essential for the engine to run properly, you probably understand many different symptoms associated with the PCV valve.

The most common symptoms of a bad PCV valve are check engine light, idle problems, faulty air-fuel mixture, misfires, and performance problems.

Here is a more detailed list of the most common symptoms when it comes to a failed or bad PCV valve.

1. Check Engine Light

Check Engine Light

A widespread problem with a faulty PCV valve on modern cars is that the check engine light is starting to flash on your dashboard. When the engine light shows up, there is a trouble code stored in the engine control module.

To read the trouble code from the engine control unit, you have to use an OBD2 scanner. Some older cars with a PCV valve fitted without an electronically controlled engine will, of course, not have this symptom.

2. High Idle RPM/Rough Idle

Car Engine Rough Idle E1609793094987

Because the PCV valve controls the airflow between the crankcase and the intake manifold, a broken PCV valve can have the same symptoms as an intake air leak, which can cause the idle RPM to get too high and other strange idle behaviors like very rough idle.

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If you have any strange idle problems, it’s always a good idea to check the PCV valve first.

3. Lean/Rich Mixture

Car Rich Mixture E1609804774815

Because of the issues previously discussed, a faulty PCV valve can have the same symptoms as an intake leak, and the air/fuel mixture can end up being wrong. In most cases, your air/fuel mixture will become lean, and you can feel the same symptoms as from a lean mixture.

Rich mixture you can often see that the car have a little bit more of gray/white smoke than usually and you can often feel a smell of petrol.

Lean mixture is more difficult to find, but it often causes misfires, as we will discuss next.

4. Misfires

Car Misfires E1609774947173

Because you can get a faulty lean/rich mixture due to a faulty PCV valve, you can feel misfires on both idle or acceleration when your PCV valve is bad.

If you have a too lean mixture, the cylinders won’t fire up correctly, which can cause misfires. If you have a mixture that is too rich, you can turn off the spark with the fuel and therefore cause a misfire.

5. Rough Acceleration

Slow Acceleration

When you have a faulty PCV valve, causing a wrong fuel mixture, you can feel that your car has rough acceleration both on high and low RPMs.

On most of the cars, you won’t feel a broken PCV valve on higher RPM’s than idle, but it’s worth mentioning because it can happen depending on the valve’s design.

6. Increased Oil Consumption & Oil leaks

Car Oil Leak E1609805239727

If the PCV valve or the hoses are blocked by moisture, you will get a very high pressure inside the engine crankcase, which will push the pressure up in the cylinders and out from the gaskets.

If you suddenly see several large oil leaks and increased oil consumption in your car, check the PCV valve and the hoses to it to make sure they’re not blocked.

7. White/Black/Blue Smoke from the Exhaust

Black Smoke Car

If the PCV valve or the hoses are blocked, the crankcase will push up oil into the combustion chambers, which will cause oil to burn inside the engine and go out through the exhaust pipe.

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This will cause a lot of blue smoke from the exhaust pipe. If the PCV valve is faulty and causing a rich or lean mixture to the engine, you can get symptoms like white or black smoke coming out from the exhaust pipe, depending on what type of mixture problem the engine has.

A short conclusion is: If you see any strange smoke from the exhaust pipe, make sure that the PCV valve is in good shape.

What is a PCV Valve?

Pcv Valve Symptoms

PCV valve stands for Positive Crankcase Ventilation, and it is one of the oldest and most used emission devices in a lot of vehicles. The PCV valve function is to eliminate crankcase emissions from the crankcase and send them to the intake and therefore combust them again in another engine cycle, which makes the engine’s emissions cleaner and more effective.

Almost all PCV valves are made in the same way; two hosing connectors with a spring-loaded one-way valve inside of it. When the engine is idle, you have a lot of vacuum inside the intake manifold, which helps the emissions get sucked out from the crankcase efficiently at lower speeds.

When you are revving up your engine and driving on higher rpm’s, the PCV valve will open further and suck out even more crankcase ventilation caused by higher RPM and faster crankcase pressure build-up.

  • Idle/Low RPM: High Vacuum, PCV Valve Half Closed
  • Higher RPM’s: Lower Vacuum, PCV Valve Open Fully
  • Backfire from crankcase: PCV Valve Closing

If you have a turbocharged engine, you do not want to boost pressure to go into the crankcase, which would cause oil leaks and blow gaskets. In this case, it’s crucial to have a one-way PCV valve.

These valves are designed differently, and the PCV valve only works on idle and low RPM’s. Some PCV valves also have 3 connectors for a vacuum, which controls them with electric vacuum solenoids. These can work in a lot of different ways, and we will discuss them in another article.

Common Trouble Codes Associated with the PCV Valve

Some common trouble codes appear when it comes to a faulty PCV valve. If you experience any of these trouble codes from your engine control unit, it’s probably time to check the PCV valve.

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Remember that just because you see these trouble codes, it’s not 100% that the PCV valve is broken. These codes can be other things also, and I always recommend you to carry out proper troubleshooting before replacing any parts.

  • P052E – Positive Crankcase Ventilation Regulator Valve Performance
  • P0171 – Fuel System Too Lean (Bank 1)
  • P0300 – Random/Multiple Cylinder Misfire Detected
  • P053A Positive Crankcase Ventilation Heater Control Circuit /Open

PCV Valve Location

Pcv Valve Location

The PCV Valve is often located on the valve cover, on the engine’s top, but it can also be located on a hose between the valve cover and the air intake filter.

Just follow the hose on the top of the car engine, and there is a big chance that you will find the PCV valve. Some cars do also have an integrated PCV valve with the valve cover.

PCV Valve Replacement Cost

A PCV Valve mostly costs between 20-50$. The labor cost is most often between 30$ to 200$ at a mechanic workshop. You can expect a total cost of 50$ to 250$ for a PCV Valve replacement.

The replacement cost of faulty PCV valves can differ significantly depending on the engine and the car you have. However, the PCV valve’s price is often meager, and you can expect prices of around $20-50 for a brand new valve.

If you think you have the knowledge to replace the valve yourself, you will not suffer from the labor costs, but remember that it can be pretty difficult to replace it if it’s located under the manifold on some cars.

If you want a mechanic to replace it for you, you can expect a labor cost of $30-200 depending on the location and the car type.

Overall, if you have an older car, the PCV valves are often easy to replace and should only take around 10 minutes, while on newer cars, there could be a replacement time of over 3 hours if it’s located under the intake. In some cases, you have to remove the intake to access the PCV valve; luckily, this is not that common.

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10 thoughts on “ PCV Valve Symptoms, Location & Replacement Cost ”

  1. I have a 1995 Honda Civic DX car with a 4 cylinder and 1.6 Liter engine. My mechanic told me that the PCV Valve Cover tube is leaking a small amount of oil and to replacement cost with his labor will cost me a total of $200.00.

    Can you tell me if this is a fair price to pay and also should I get the PCV Valve Cover and Hose replaced as soon as possible? What kind of damage will be done if I don’t get the PCV Valve Cover and Hose replaced?

    Thank you,

    1. I have bmw328i base conv 3.0. I know the pcv valve is on the valve cover. I need yo kknow wheee ghe other end of hose attaches. It had no hose on it when i bought car so i dont bave a clue. Thanks for whatever you can tell me

  2. Hi! I drive Audi a 4 b 8 2013 with CVT gearbox! And have an issue: the engine starts only from second attempt when it is hot weather (first attempt doesn’t gathering cold rpm’s – 1200, but only 600-400, second attempt is always ok). And another one: when in traffic or parking always pressing the brakes rpms are dropping down for one second. No check engine! Idle rpms are ok -800, dropping only when operating with brakes! Any ideas?! Thanks in advance!

    1. My name is jeremy,
      Im writing this in regard to my 1999 chrysler 300M. I noticed some white smoke coming from my exhuast .. I bought the car used from a private person. I knew their were going to be issues. All in all great car. I changed oil and oil filter. It was fine. 2 days later i seen white smoke. I have no idea about cars. What should i do?

  3. M Y husband has a 2008 BMW. My question is can a bad PVC heater valve cause frothing or condensation Under the oil cap? Thank you!

  4. Hi bro

    My name is Eric. I have bought a second hand Volkswagen Tiguan 1.4 TSI engine type CAVA since November 2019. Two day after having purchased the car I noticed that there is white smoke coming out of the exhaust pipe that last for about 20 seconds in the morning and evening when i return back home (about 10 hours at rest). I have it inspected by 3 mechanics and all have come to the conculusion that there is lack of compression and missfires in at lest one cylinder. Grateful if you could provide advise to what may be the cause of these symptoms. Thanking you for your support.

  5. I have 2009 Toyota innova D4d, There is oil on intake side of turbo, does worn PCV valve has something to do with this?

  6. Is it common that after replacing a bad pvc valve which was causing oil consumption that the engine have some white smoke when first started but then fades away ?

  7. Can I remove the pvc if it is bad without replacement and if I do,what is the effect on the crank shaft. Can I block the intake manifold side?

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