What is PCV?

I have heard this term for several times and have no idea what it is. Can anyone help me out? And under what condition should i change it? Thanks.

The PCV (positive crankcase ventilation) Valve and Breather Element work together within the car’s emissions and ventilation systems. They serve as part of the emissions control system by recirculating unburned gases and fumes back through the intake manifold to be reburned. Therefore these gases and vapors are not expelled through the exhaust system so air pollution is reduced.

What are the benefits of replacing the PCV Valve and Breather Element?

Loss of power, oil dilution and even engine failure are avoided
Oil life is extended and engine lubrication is improved
Oil consumption, rough idle and air filter contamination are avoided
Environmental pollution is reduced
How often should the PCV Valve and Breather Element be replaced?

Generally the PCV Valve should be replaced every 12 months or 12,000 miles. The breather element should be replaced at the same time or anytime it fails a visual inspection. Your Grease Monkey manager will check the resource manual specifically for your car’s recommended service requirements.

Thanks, great information.

I just searched under the hood and could not locate it. Can anyone tell me where is it and how to detach it?

Looking at the engine from the front of the car, it's on the right top rear of the head cover attached to a short hose. You detach the hose and pull the PCV valve from the head cover.