How To Replace PCV Valve: The Cheapest Yet Most Efficient Component!

PCV or positive crankcase ventilation is a tiny valve device. PCV makes use of the intake manifold that is the supplier of fuel/air mixture to the cylinders. The valve draws the combustion gases and sends them back to the engine using the manifold. Today, it is about “how to replace PCV valve” because when PCV malfunctions, it does not utilize those gases, and they pass to the atmosphere.

How to Replace PCV Valve: Test the Valve and Replace it Accordingly

To replace a PCV valve, you should first make sure if it really needs a replacement. Get to the engine hood and open it up. There you need to locate the PCV valve that, in most cases, is located near the intake manifold in case you don’t know “where is the PCV valve located.”

The valve stays connected to a hose that you should remove in the first place.

Once you remove the hose, you can pull off the valve and take it in your hands

Now, here comes the testing phase to determine if the valve is malfunctioning or not. You need to shake it up and listen to that clattering sound of metal. If you can hear the metal sound, then the valve is working; else, it needs a replacement.

There is another way to make sure if it is the PCV valve that is malfunctioning. You should also have a check about other connecting parts such as the vacuum.

What’s Next?

Warm up the engine for about 20 minutes and then get to the hood.

Now access the valve cover and disconnect the valve. Block the valve with your fingertip, and you would feel a sucking effect. You would notice a drop of 40 to 80 rpm; if the fall is more than that, it indicates that the PCV valve is left open.

If you notice no sucking at your fingertip, it is the blocked valve and hose that you can clean using a lacquer thinner and a hose brush.

Once you remove the hose, you can pull off the valve and take it in your hands
The PCV can be located under the hood of the engine (Photo Source: youtube)

See More:

Consequences of Oil in Intake Manifold

The Explanation on PCV Valve Functioning

A valve is the cheapest device of the engine’s system that you can get for just $5. You can replace the old valve with the new one and put that hose back to secure the valve in place.

This way, you easily replace the PCV valve; start your engine, and check if there is an oil leak around the valve. So, before getting on with “how to replace PCV valve,” make sure that the PCV valve is the culprit.

Tip: Not all automobiles feature a PCV valve; make sure your vehicle has it.

How PCV Works? Digging Deeper Into the Mechanism

Now that you know how to replace PCV valve, let’s head to its working.

The crankcase where the crankshaft and engine oil happen also houses the PCV valve. The pistons and axles are two other primary parts that make the vehicle move by powering the engine by making certain moves.

When the move happens, some gases get released around the piston and into the crankcase. If here, the gases mix up with the engine oil, the oil forms a creamy buildup that clogs the passages and can blow those seals and gaskets.

These gases that go into the crankcase can’t be released directly into the air. The gases contain about 70% of unburned fuel, and hence, directing them into the air won’t be wise.

The PCV valve functions as a solution by catching these useful gases and directing them into the intake, so they can be burned to provide vehicle the energy.

There is a breathing tube as well that allows fresh air to enter, so the whole circulation can remain clean, and no fuel gets wasted. Now, you can understand if the tiny valve goes bad, how much fuel would be wasted.

Tip: If the PCV valves work fine and you still notice the symptoms, take your car to a professional repair shop.

There is a breathing tube as well that allows fresh air to enter for complete cleaning inside
PCV valve functions as a solution by catching gases to intake for proper energy production (Photo Source: chromium)

Symptoms of a Failing PCV Valve

If you can encounter any of these symptoms, do check the PCV valves and consider changing PCV valves.

Excessive Oil Consumption and Leak

Excessive oil consumption is the most common symptom of a bad PCV valve. When the PCV valve fails, it does not manage the pressure in the crankcase, which affects all the seals and gaskets. As there is no other way for the pressure to be released, the oil drips through the seals.

So, if you notice oil leaking on the floor or beneath the vehicle, it is a sign that the PCV valve is problematic.

Contaminated Filter

The increased pressure in the crankcase also makes the breather filter to be contaminated. The hydrocarbons and oil build up in the filter and block the overall airflow. Due to the increased pressure, the water vapor or the moisture gets mixed with the gas, which causes this build-up.

To check it easily, you need to get to the filter and check there for any build-up. We hope this clears the sign and how to replace PCV valve easily.

Overall Poor Performance

As the pressure builds up in the crankcase and the airflow becomes poor, it affects the overall performance of a vehicle. When the PCV valve does not open and closes at the right time, oxygen enters the combustion chamber. This makes the overall air/fuel mixture leaner and causes the engine to provide poor performance.

In any of the cases, diagnosing the PCV valve comes as the easiest solution before you deal with other technicalities. Do not let the car consume excessive oil because it will only lead to more build-up. If you are not able to take your car to the nearby repair shop, call professional at your place and let them handle the issue. Manage your vehicle for the speed sensor and more issues by reading the Maintenance Tips.

Overall Poor Performance can also lead to a bad PCV
Excessive oil consumption is the most common symptom of a bad PCV valve (Photo Source: automoss)

Signs and Symptoms in a Nutshell

  • Increased internal engine pressure
  • Gaskets or leaks malfunctioning
  • Engine oil leaks or finding oil on the floor
  • Finding sludge in the filter or internal components
  • The engine produces black smoke

When the PCV gets stuck in an open position or when the hose gets disconnected, the leak makes you notice these symptoms-

  • Engine misfires at idle
  • Lean air-fuel mixture
  • Increased oil consumption
  • Hard engine start
  • Presence of engine oil in PCV valve or hose
  • Rough engine idle


If you can’t get through the issue on your own, calling a professional is the easiest thing to do. Those who are comfortable to handle the replacement can make use of this guide about “how to replace PCV valve.”