How do you know if your PCV valve is stuck open?
Since the combustion chamber is burning oil coming from the stuck open pcv. It will produce blue
Common signs of a faulty PCV valve include excessive oil consumption, oil leaking, a blocked breather filter, and reduction in overall performance.
A clogged hose or PCV system or inoperative valve can increase oil consumption because pressure builds when the vapors in the crankcase aren't allowed to flow into the combustion chambers. That additional pressure can force oil past seals and gaskets.
If you need to drive a couple miles to get the parts needed then plug the vacuum side of PCV line and it may be okay to drive a short distance since running longer than this may cause the pressure to build up in the crankcase and cause oil leaks and engine will run lean or rich without a properly functioning PCV system ...
The PCV valve is easily one of the most important parts of your car, and although it is possible to continue to operate your car with a bad valve, it is not recommended as it can corrode your car's engine over time.
The PCV valve regulates how much vacuum can pull through the crankcase. It's hooked into the intake - when the vacuum is high at idle, the PCV valve stops most of that vacuum. As vacuum drops with an increase in RPM, The PCV valve opens, to allow a higher volume of gasses and pressure to be pulled into the intake.
Answer: Usually, a PCV valve is normally closed when the engine is not running; as the engine accelerates, the valve opens to allow blowby gases. So you shouldn't be able to pass air flow in both directions. However, some models like the '87 Escort, use a fully open valve design.
you have a bad PCV valve are rough idles and a lean air to fuel mixture. These two problems cause an issue with the air intake due to the bad PCV valve. Many of the symptoms of a faulty PCV valveare the same as an intake air leak.
a faulty pcv valve can cause a number of problems: 1. rough idle or stalling: if the plunger is stuck open, the pcv valve will allow too much air to enter the engine. this can cause a lean air-fuel mixture, resulting in a rough idle or stalling.
The stock valve pulls vacuum from the intake manifold to open the valve and when doing so pulls hot oily vapor into your intake manifold. The main benefit of "deleting" this is to lower intake temps and keep oily vapor from going back into your intake. The stock PCV valve can make an oily mess of an intake manifold.
How do you unclog a PCV valve?
I cover how to clean plastic PCV valves. What can I use to ... - YouTube
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. This will cause a lot of blue smoke from the exhaust pipe.

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. The PCV (positive crankcase ventilation) valve is a one-way valve that recycles crankcase gases back into the engine to burn.
If the PCV valve or the valve hose is leaking, the engine might start making strange noises as a result. In particular, you might hear a whistling or a hissing sound coming from under your hood. This sound is caused by air rushing out of the hole in the valve or the valve hose.
Suppose the PCV valve hose breaks; there will be PCV oil consumption. That is to say, the gas will not go back into the engine, and the engine will experience a loss of power and have increased emissions. In this article, we'll discuss at length how you can test and replace your PCV valve and bad PCV valve symptoms.
If you experience hesitation, surging or an oil leak, it may be a sign of PCV valve problems. Your vehicle's owner's manual may give a recommendation for when the PCV valve should be replaced - usually between 20,000 mi/32,000 km and 50,000 mi/80,000 km.
It's really a pretty simple system, but does an important job. The re-circulating air removes moisture and combustion waste from the crankcase, preventing sludge. This extends not only the life of your oil, but the engine as well. The PCV relieves pressure in the crankcase, preventing oil leaks.
Specifically, if the PCV valve malfunctions, or is stuck open, it allows some of the oil that is used to lubricate the pistons and cylinders to escape. This wayward oil can then find its way to the surface of the engine's spark plugs, resulting in a condition known as “oil fouling.”
If your vehicle's PCV valve isn't working, you can clean it yourself by immersing it in carburetor cleaner or solvent your auto supply store deems suitable. There should be no gummy deposits or discoloration on a clean valve.
A typical PCV system should be pulling about 1 to 3 inches of vacuum in the crankcase at idle. If you see a significantly higher vacuum reading, the intake manifold gasket is probably leaking and pulling vacuum on the crankcase.
Is PCV valve open at idle?
Answer: Usually, a PCV valve is normally closed when the engine is not running; as the engine accelerates, the valve opens to allow blowby gases. So you shouldn't be able to pass air flow in both directions. However, some models like the '87 Escort, use a fully open valve design.
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. The PCV (positive crankcase ventilation) valve is a one-way valve that recycles crankcase gases back into the engine to burn.
Another symptom of a bad or failing PCV valve hose is your vehicle will misfire while it is idling. This can be from a loss of vacuum due to the hose not working properly because of a leak, the hose being pinched, or becoming clogged from buildup over time.
Specifically, if the PCV valve malfunctions, or is stuck open, it allows some of the oil that is used to lubricate the pistons and cylinders to escape. This wayward oil can then find its way to the surface of the engine's spark plugs, resulting in a condition known as “oil fouling.”