Back to all

PCV Valve: What Is It?

December 10, 2017

Most Joliet drivers know something about preventive maintenance on a vehicle. We know we should routinely replace the oil and wiper blades and other fluids. But have you heard of a PCV valve ? This little car part needs to be replaced regularly or it can cause some serious problems in your vehicle engine.

PCV stands for Positive Crankcase Ventilation. The crankcase holds your motor oil and is located at the bottom of your engine.

When fuel is burned in your engine, it produces waste gases that are mostly vented out through your exhaust system. But some of these gases push their way past the pistons and into the crankcase. There, these gases can mix with motor oil to produce oil sludge, which can damage vehicle engine parts through corrosion and by clogging engine passages. Joliet vehicle owners should be advised that if the engine is running at high speeds, these gases can also cause pressure inside the crankcase to build up. This pressure, in turn, can blow gaskets and damage seals, leading to oil leaks.

The waste gases that leave the engine are comprised of about 70% unburned fuel. They used to be vented off the crankcase into the atmosphere. But starting in 1964, laws mandated that these gases be recaptured. Manufacturers began installing PCV systems, which recycled the gases into the air intake system where they could be mixed with fuel and sent to the engine to be burned.

The PCV valve is a one-way valve attached to the crankcase. Waste gases exit the crankcase through the valve but cannot enter.

Over time, the waste gases leave deposits on the PCV valve that can gum it up. So it needs to be replaced occasionally. This is an inexpensive part of preventive maintenance that is often overlooked, but which can have very expensive consequences. It's good auto advice to keep this little valve clean and working well.

In order to maintain efficient circulation, the PCV system also has a breather tube that allows clean air to enter the crankcase. This air is usually filtered through the engine air filter. But some vehicles have a separate air filter for the breather tube called the breather element. If this is the case with your vehicle, proper maintenance of the PCV will include replacing this element. To find out whether your vehicle has this type of PCV system, check your owner's manual or ask your service advisor at Tuffy Joliet (South Plainfield).

The PCV system reduces harmful vehicle emissions. The maintenance it requires is simple and inexpensive at Tuffy Joliet (South Plainfield). A fouled or damaged PCV system can lead to serious engine damage for Joliet drivers.

Let's all learn to practice good car care. It's good for our wallets, and it's good for our Illinois environment.

Tuffy Joliet (South Plainfield)
2031 SR 59
Joliet, Illinois 60586
815-436-1829

More articles from Tuffy Joliet

No Charge (Why Won?t My Battery Hold a Charge?)

December 14, 2025

When your vehicles battery is dead, it leaves you with that horrible, helpless feeling. A dead battery means it wont hold a charge, and there are several reasons it wont. One is age. Batteries have chemical and electrical systems in them that create power, and as time goes by, they wont work we... More

All Lined Up (Alignment Inspection)

December 7, 2025

When you head down a straight road, does your vehicle pull to one side? Do you feel vibration in any of the wheels? If you've noticed any of these things, it's probably time for you to get your wheel alignment checked. When your vehicle left the factory, its wheels were parallel to each other an... More

Why did my vehicle fail its emissions test?

November 30, 2025

We all want to breathe clean air and keep our planet green. One of the ways to do that is by requiring all vehicles with internal combustion engines to pass an emissions test. Thats because these vehicles can be big polluters. Everyone wants their car to pass the test so they can continue the... More