1. About.com
  2. Autos
  3. Auto Repair
Filed In:
  1. Auto Repair
PCV VALVE

Definition: The Positive Crankcase Ventilation valve is an emissions control device that routes unburned crankcase blowby gases back into the intake manifold where they can be reburned.
The PCV system is one of the oldest emission control devices, and also one of the most beneficial. Besides totally eliminating crankcase emissions as a source of air pollution, the constant recirculation of air through the crankcase helps remove moisture which otherwise would cause sludge to form. Thus the PCV valve extends the life of the oil and engine. The PCV valve requires little maintenance. The valve and filter should be replaced somewhere around 30,000 to 50,000 miles (see the vehicle owners manual for service intervals).

<Back to Last Page> <Full Glossary>

© 2000 - 2002 Vincent T. Ciulla

©2012 About.com. All rights reserved. 

A part of The New York Times Company.