what does a pcv valve do?

Answer 1

It vents your crank case. If it's plogged, you can continually blow the dipstick out of the oil checker. That happened to me!

Answer 2

PCV stands for positve crankcase ventilation. what it does is this:

DESCRIPTION
System
Positive Crankcase Ventilation (PCV) system is used to prevent blow-by gases from escaping to the atmosphere by routing them through a vacuum controlled ventilation valve, into the intake manifold. Fresh air from the air cleaner is pulled into the crankcase, mixed with blow-by gases and then combined with the air/fuel mixture and are burned in the combustion chamber.

PCV Valve
The primary control is through the PCV valve which meters the flow at a rate dependent upon manifold vacuum. To maintain idle quality, the PCV valve restricts the flow when intake manifold vacuum is high. If abnormal operating conditions arise, the system is designed to allow excessive amounts of blow-by gases to back flow through the crankcase vent tube into the air cleaner to be consumed by normal combustion.

CONSTRUCTION
PCV Valve
The PCV valve, consists of a needle valve, spring and housing.

OPERATION
Engine Off
When the engine is "OFF", the spring holds the needle valve closed to stop vapors from entering the intake manifold.

Engine On
When the engine is running, manifold vacuum lifts the valve "OFF" its seat and allows crankcase vapors to enter the intake manifold.

Engine Backfire
In case of an engine backfire, in the intake manifold, the valve closes. This stops the backflow of gases and prevents the ignition of fuel vapor in the crankcase.

Excess Blow-by
During certain engine conditions, more blow-by gases are produced than the PCV valve can handle. In this case, the excess gases are returned through the air intake tube to the air cleaner or intake manifold, where they are burned in the combustion chamber.

Answer 3

Stands for Positive crank Case Ventilation and buy the way of vacuum it sucks gasses back into the motor so they can be Burt again part of the smog feature of any vehicle , old term burning blow by from the engine the old vehicles like a 1952 Chevy there was a pipe the came out of the valve cover and went down under the car and was vented into the air so this was one step towards clean air act

Answer 4

A PCV VALE COLLECTS THE IMPURITIES IN THE GAS LINE ,TRY USING A HIGH GRADE OF GASOLINE FOR A WHILE

Answer 5

Here's a diagram:
http://autorepair.about.com/library/glossary/bldef-625.htm

And another:
http://autorepair.about.com/cs/generalinfo/l/bldef_621.htm