What Is a PCV Valve?

The PCV valve is part of the crankcase ventilation system that reroutes harmful gases to the engine combustion chambers to burn out in a safer way.
Written by Abbey Orzech
Reviewed by Melanie Reiff
background
A PCV valve, or positive crankcase ventilation valve, is attached to your vehicle’s crankcase to reduce harmful emissions. It routes the harmful gases released from the crankcase into the engine’s combustion chambers, where they are more safely burned out.
Unless you deal with the inner workings of vehicles often, you may have never heard of the PCV valve. It’s one of those engine components you don’t think about until you have to, but PCV valve malfunctions can create a host of issues that lead to serious engine problems.
That’s why
Jerry
, the
top-rated brokerage app
that finds users hundreds of dollars in annual
car insurance
savings, has formulated this guide on all the PCV valve need-to-knows. We’ll go over its role in your vehicle, how to know when it may need replacing, and the typical cost of that replacement.
Are you getting ripped off on your car insurance? Find out in less than two minutes.
No long forms · No spam · No fees
Find insurance savings
4.7/5 Rating on App Store

What is a PCV valve?

A PCV, or positive crankcase ventilation valve, is a one-way valve positioned on your vehicle’s crankcase. The crankcase sits at the bottom of your engine near the intake manifold. It holds the engine oil and takes in some of the gases produced when your engine burns fuel. 
The PCV valve is a one-way valve attached to the crankcase to redirect the gases that flow in the crankcase to the engine combustion chamber so they’ll be burned safely. Before PCV valves were used, those harmful crankcase gases were released out the exhaust system. 
This engine component was among the first automotive emission-controlling technologies in the US and has been installed in all internal combustion engines since 1964.
MORE:How to pass emissions testing

What does a PCV valve do?

The PCV valve exists both to make the emissions from a vehicle less harmful and to increase the general performance of a vehicle. It helps with emission control by directing the crankcase gases into the engine’s combustion chamber to be converted to less harmful gases before they’re released.
Without the PCV valve, the waste gas produced from burning fuel would build up in the engine crankcase and mix with the motor oil to create oil sludge
As you can probably imagine, oil sludge in the engine can really gum up the works and lead to expensive corrosion and clogging damage.
This can all start to happen with a faulty PCV valve as well, so it’s important to ensure the component is in proper working order to avoid lasting engine damage.

Symptoms of a bad PCV valve

But how can you tell if your PCV valve is on the fritz? Pay attention to your car’s engine behaviors and some of these other tell-tale signs of a bad PCV valve. You can have a mechanic check the situation out to know for sure.

Check engine light on

Okay, we know that the check engine light can come on for a ton of reasons, and it won’t always be simple to tell a bad PCV valve from a loose gas cap with just this light itself. But an illuminated check engine light is one of the first signs of a bad PCV valve.
If you see your check engine light turn on, use an onboard diagnostic (OBD) tool if your car comes with that, or bring your car to a mechanic to check the code and identify the problem.

High idling

High idlingis another sign of a failing PCV valve. Rather than the slow and low idle vehicles are supposed to have when the engine is running but the car is stopped, a high idle is just that—higher. The engine will sound like it’s doing more work than it needs to be.

Rough idling

On that same token, your PCV valve may be bad if your vehicle rough idles. Rough idling happens when your engine bounces sporadically between a regular low idle and high idle, sometimes sputtering.
This can also happen because of a dirty air filter, spark plug problems, or issues with the oxygen sensor, so you may wish to investigate further before ruling the issue a bad PCV valve.

Wrong air-to-fuel ratio

The function of the PCV valve impacts the engine’s air intake, so if the valve is clogged or otherwise malfunctioning the engine’s air-to-fuel ratio can be thrown off. Without the appropriate mix of air and fuel, the engine will either underperform and run lean or overcompensate and run rich. Either scenario puts unnecessary strain and wear on the engine system.

Engine misfires

You can tell if your engine misfires by sound. It can be quite a loud bang, resembling the sound of a gunshot or other explosive—but maybe not as damaging as that.
A misfire is caused by the engine running too lean or too rich from an incorrect air-to-fuel mixture. It will wreak havoc on your engine’s systems if not taken care of as soon as possible.

Rough acceleration

A bad PCV valve could also lead to a rough acceleration and stuttering engine. With a functioning PCV valve, your car should be able to get up to the desired speed relatively smoothly and without stalling or running at too low of an RPM.

Oil leaks

As its function is to redirect gases and lower pressure within the crankcase, a malfunctioning PCV valve will instead contribute to a rise in crankcase pressure. The extra built-up crankcase pressure can wear on components like the gaskets and lead to oil leaks.

Excessive oil consumption

If there’s an oil leak, you can bet the engine is recording excessive oil consumption too. The PCV valve is unable to release the excess gas pressure within the crankcase, and since it will have to be released somehow, the oil is forced out.
Not only will you need to shell out for an oil change sooner than otherwise necessary, but the lack of lubrication in the engine also means more friction wearing on your engine components.

Engine sludge

As discussed earlier, among the PCV valve’s duties is the removal of gases produced from burning fuel so they won’t mix with the crankcase’s motor oil and produce engine sludge. Engine sludge can lead to engine damage and a worsened fuel economy.

Poor fuel economy

To continue on that note, a bad PCV valve can lead to poor gas mileage! In general, a functioning PCV valve allows the other systems in your engine to perform their jobs and keep the engine working in healthy order. 
When those systems are not able to work effectively, your fuel economy will suffer.
Let Jerry find your price in only 45 seconds
No spam · No long forms · No fees
Find insurance savings

When to replace your PCV valve

With all of these potentially really damaging consequences of a bad PCV valve, you may be looking for some easily placed benchmarks to keep track of replacement needs. Unfortunately, there is no specific timeframe to adhere to for PCV valve replacements.
Essentially, the PCV valve works until it doesn’t. You’ll need to keep your senses out for symptoms of a failing PCV valve, like:
  • Oil leaks
  • Sludge around the engine
  • An illuminated check engine light
  • Unfamiliar engine noise
  • Reduced vehicle performance
If you suspect your PCV valve is malfunctioning, you’ll need to replace it as soon as you can to avoid costly engine damage and auto repairs.

How much does a PCV valve replacement cost?

Happily, replacing a PCV valve is one of the most inexpensive engine component replacements out there. The part itself usually costs between $10 and $15, but you’ll need to factor in the cost of labor as well.
Labor costs will vary depending on where you’re getting the repair done, too. Dealerships tend to charge more than your local repair shop, but go wherever you’re comfortable! The entire PCV valve replacement—parts and labor included—will typically run you between $25 and $110.

How to find cheap car insurance

PCV system repairs are on the less expensive side of things, but most other engine repairs are not. And sometimes they’re totally unavoidable. Such is the life of a car owner.
But what if we told you finding a better
car insurance
rate with
Jerry
could help you save essential time and money on taking care of your car?
It’s this simple: download the Jerry app or go to
getjerry.com
. As a licensed personal broker, Jerry collects information from your existing insurer and finds you the best deals at your coverage level in as little as 45 seconds. 
Choose from competitive quotes from top insurance companies and Jerry takes care of the rest—securing your new policy and helping you cancel your old one upon request. 
No long forms. No calling around. No hard work. Just savings. The average Jerry user saves over $800 a year on car insurance.
Jerry
was spot on. I’m young with one rear end on my record. Still, they dropped my monthly insurance rate from $468 to $250. This really saved me money.” —Jason M.

FAQs

It depends on the type of car you drive! PCV valves and similar technology like orifice tubes are necessary for internal combustion engines to avoid engine damage and the production of super harmful emissions. But if you’re driving an EV, you have no need for a PCV valve!
The PCV valve is typically made of a metal head attached to a silicone, polyurethane, or rubber hose. It’s sealed to the valve cover via a rubber grommet.
Estimate your repair costs for free with GarageGuard™
Simplify your car maintenance with Jerry.
Try GarageGuard™

Easiest way to compare and buy car insurance

√
No long forms
√
No spam or unwanted phone calls
√
Quotes from top insurance companies
Find insurance savings