The PCV valve is necessary to prevent the gasses from going backwards out the breather when there is no vacuum. As others said you could go without it but you'll spew these very bad gasses, even into the passenger compartment. There is no loss in performance with a properly running PCV..
People also ask, can you run a car without a PCV valve?
If you don't want to use a PCV valve, you could just run a hose from a valve cover down to the bottom of the frame somewhere. Leave it uncapped and pointed rearward, and air moving past it as you drive will create some vacuum. This is how it was done before the EPA crawled up our asses.
Secondly, what are the symptoms of a bad PCV valve? Symptoms of a Bad or Failing PCV Valve Hose
- Poor fuel economy. If the PCV valve hose is clogged or has a leak, it may cause poor fuel economy.
- Check Engine Light comes on. The Check Engine Light may come on for a variety of reasons, and one of them is a failing PCV valve hose.
- Misfiring while idling.
- Noise from the engine.
Accordingly, is it necessary to run a PCV valve?
Run a PCV valve it doesn't cost you any HP. The PCV sucks the crankcase fumes or blow-by from your engine. If you don't run one, usually you will get fumes in the car from blow-by and it makes a mess if your valve covers as your breathers will fillup quickly. Run a PCV valve it doesn't cost you any HP.
What happens if PCV valve is disconnected?
A defective PCV valve will fail to vent exhaust gases in the engine. These gases will build up pressure inside the engine, causing oil leaks and other problems. A PCV valve that fails to work properly will restrict the amount of air entering the engine, causing idle problems and reducing fuel efficiency.
Related Question Answers
Why is my PCV valve full of oil?
The PCV valve is typically found in the engine valve cover. When the amount of blowby exceeds the full capacity of the PCV valve, the gases are rerouted from the intake manifold, to the engine air cleaner assembly. This can leave oil in the air filter or its housing, and isn't ideal.Does a PCV valve affect performance?
As the PCV valve starts going bad, the performance of your vehicle will get worse. This can be exhibited by a buildup of pressure in the exhaust or the engine could stall out. The bad PCV valve may not close all the way, so oxygen may get into the combustion chamber.How do you know if your PCV valve is bad?
Symptoms of a Stuck PCV - Engine misfires at idle.
- Lean air-fuel mixture.
- Presence of engine oil in PCV valve or hose.
- Increased oil consumption.
- Hard engine start.
- Rough engine idle.
Will a bad PCV valve cause white smoke?
If the PCV valve faulty and causing a rich or lean mixture to the engine, you can get symptoms like white or black smoke coming out from the exhaust pipe depending on what type of mixture problem the engine has.What happens if PCV valve stuck open?
A stuck closed PCV valve will cause excessive crankcase pressure. This excessive pressure results in leaking oil seals and gaskets. A stuck open valve or leaking PCV hose will cause drivability issues like surging. At idle, with the PCV valve removed from the valve cover, there should be vacuum at the PCV valve inlet.What is the purpose of a PCV valve?
A PCV valve that's supposed to regulate the flow of these gases is the heart of most PCV systems (some newer vehicles don't have a PCV valve). The PCV valve routes air and fuel from the crankcase back through the intake manifold to the cylinders rather than allowing them to escape into the atmosphere.Can I run my engine with the valve covers off?
People have been running engines with the valve covers off, without damage, forever. It can be messy, but not damaging. One old trick if you have a spare set of valve covers, cut the top out of one set so they basically form a wall around the head.What does a PCV valve connect to?
A hose connects the PCV valve to the intake manifold. A second hose between the air cleaner and crankcase or other valve cover (V6 or V8 applications) provides fresh air to help flush the vapors out of the crankcase. Some engines have a separate air filter for the PCV breather hose located inside the air cleaner.Can I just clean my PCV valve?
Clean it yourself by immersing it in carburetor cleaner. There should be no gummy deposits or discoloration on a clean valve. If your PCV valve must be replaced, buy a new valve, remove the old one, and insert the new one in its place.Is a PCV valve one way?
The PCV (positive crankcase ventilation) valve is a one-way valve that recycles crankcase gases back into the engine to burn. A plugged PCV valve can result in a rough idle and poor mileage. And never replace a PCV valve simply because it 'looks dirty. ' All used PCV valves look dirty.Does PCV valve affect gas mileage?
Poor fuel economy If the PCV valve hose is clogged or has a leak, it may cause poor fuel economy. This is because the vacuum on the intake side of the cylinder head will not be able to properly signal the correct amount of fuel that needs to be fed into the engine and can result in a lean or rich engine condition.How much does it cost to replace a PCV valve?
The average cost for a PCV valve replacement is between $59 and $81. Labor costs are estimated between $42 and $54 while parts are priced between $17 and $27. Estimate does not include taxes and fees. When would you like to drop off your car?Can you drive car with bad PCV valve?
Although its never recommended to drive any longer than you should with a damaged component, driving 12 hours with a damaged PCV valve could be very risky. These excesses gasses are transferred the rough the PCV valve hose. This system allows the vehicle to utilize excess gas, so that it is not wasted.What does PCV stand for?
Positive Crankcase Ventilation
Can a bad PCV valve cause a vacuum leak?
If the PCV valve did not regulate air flow, the engine would act like it had a vacuum leak. Too much air flowing into the intake causes the engine to lean out [too much air in relation to the fuel] and misfire. At an idle, the PCV valve restricts air flow, to reduce this problem.Can a bad PCV valve cause hard starting?
If the pintle inside the PCV valve sticks open or the spring breaks, the PCV valve may flow too much air and lean out the idle mixture. The PCV may cause a rough idle, hard starting and lean misfire (which increases emissions and wastes fuel).Can a bad PCV valve cause overheating?
Simply put, the PCV isn't causing your problems. Most common causes of overheating are thermostat (most common by a big margin), poor coolant quality, worn water pump and blocked radiator.Does a PCV valve need vacuum?
PCV valve or orifice The PCV valve (positive crankcase ventilation) is a variable orifice that controls the flow of crankcase fumes, admixed with fresh air admitted to the crankcase by the breather, into the intake tract. So at high manifold vacuum, the PCV valve allows only a low flow rate. 
