How do I know if my Subaru PCV valve is bad?

How to Determine if Your Subaru PCV Valve is Bad
To determine if your Subaru PCV (Positive Crankcase Ventilation) valve is bad, you can look for certain symptoms and perform some checks. Here are some signs that may indicate a faulty PCV valve:
1. Rough Idle: A bad PCV valve can cause a rough idle, where the engine may shake or vibrate when at a standstill.
2. Excessive Crankcase Pressure: If you notice excessive pressure building up in the crankcase, it could be a sign of a bad PCV valve.
3. Poor Fuel Economy: A failing PCV valve can lead to poor fuel economy. If you notice a decrease in gas mileage without any other apparent reason, it may be worth checking the PCV valve.
4. Increased Oil Consumption: A faulty PCV valve can cause increased oil consumption. If you find yourself needing to add oil more frequently than usual, it could be due to a bad PCV valve.
5. Smoke or Fumes: A malfunctioning PCV valve can cause smoke or fumes to come out of the exhaust. This can be accompanied by a burning oil smell.
To further diagnose the issue, you can perform the following checks:
1. Inspect the PCV Valve: Check the PCV valve for any signs of damage or blockage. If the valve is clogged or broken, it may need to be replaced.
2. Check the Breather Element: The breather element, which is connected to the PCV valve, can become contaminated with oil and hydrocarbons if the PCV valve is failing. Inspect the breather element for any buildup.
3. Measure Gas Mileage: If you suspect a bad PCV valve, monitor your vehicle’s gas mileage. If it starts to decrease without any other explanation, it could be a sign of a faulty PCV valve.
It’s important to note that these symptoms and checks are not exclusive to Subaru vehicles and can apply to other makes and models as well. If you’re unsure about the condition of your PCV valve or need assistance with the replacement process, it’s recommended to consult a qualified professional or refer to your vehicle’s manual for specific instructions.
Remember, regular maintenance and timely replacement of the PCV valve can help ensure the proper functioning of your vehicle’s emissions control system and prevent potential issues down the line.
I hope this information helps! Let me know if you have any other questions.

How do you tell if a PCV valve is stuck open?

This is why your car has a rough idle. The third symptom could be a stalling engine in some situations. If there’s too much air coming from the crankcase.

What happens when the PCV valve goes bad?

An oil leak may cause the car to burn oil and cause oil to leak from under the car foreign engine misfiring the engine misfiring is also a sign of a faulty PCV valve. Most commonly the misfire occurs

How do I check my PCV valve at home?

Check the PCV valve with the engine running
You can also check it in place with the engine running. Pull the PCV valve from its housing and place your thumb over the PCV valve opening. You should feel it click. If the click sounds or feels mushy, replace the valve.

How do you check a PCV valve on a Subaru?

Since they are “shaker” valves, the best way to check them is to remove them and give the a rattle. Old one basically doesn’t rattle at all compared to the new one as shown in the video.

How can you tell whether a PCV valve is bad and needs to be replaced?

One way to check whether a PCV valve is functioning is to remove it from the hose or tube and shake it. If you can hear a metallic rattling noise, it’s likely in good working order. If you do not hear anything when you shake the valve, it is likely that it is no longer opening and closing like it should.

Will a bad PCV valve throw a code?

If the device detects a problem with the PCV system, it will turn on the check engine light and store a corresponding diagnostic trouble code in memory. A stuck-open PCV valve can also disrupt the air-fuel mixture and cause misfires that trigger the check engine light.

When should I replace my Subaru PCV valve?

Unlike changing your battery or oil, there is no particular time frame to replace your PCV valve. As long as a PCV valve is functioning properly, you do not need to replace it. However, they are subject to damage due to a lot of blow-by gases traveling through them which can sludge the valve up.

Can a PCV valve be bad even if it rattles?

However, the fact is that if a PCV valve “rattles” when one shakes it, the moveable part that keeps the valve closed is no longer held in position under spring tension, which means that the valve is actually defective and useless.

What happens when a PCV valve goes bad?

If the PCV valve or the hoses to it are blocked, the high pressure in the crankcase will push engine oil into the combustion chambers, where the oil will be burned and go out through the exhaust pipe. Burning oil will cause a lot of blue smoke from your tailpipe.

What are the three signs of a bad PCV valve?

What are the signs of a faulty PCV valve?

• excessive suction on the oil cap.
• a discolouration or film-like residue forming on the underside of the oil cap.
• whistling noises coming from the engine.
• the emission of white exhaust smoke.