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what does a PCV valve do?


89BuickRegalGS

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A Positive Crankcase Ventilation (PCV) valve recirculates gases from the valve covers and extra pressure in the head through the intake manifold to be reburned... it's mainly for emissions.

 

As for replacing it, about every 30K miles or if you can check it often, whenever carbon / oil build up is found. They really don't go bad, they just need to be cleaned using some solvent from a arasol can (brake / throttle body cleaner).

 

- RedFox340

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thanks for the response. whenever i bought a used car, my dad would change out the PCV valve on it. what are the symptons of a bad one?

does it screw up the engine?

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i got a little filter on the back of the plenum were the tube that connected to the intake goes...wanted to know if this a prob and if this could affect th PCV system? also, wat if i ran cold air induction by placing the breather in a clooler place, would this be any effectivef?

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It's not that big of deal, mainly when you let of the gas, pressure within the engine is recirculated; a clogged one can stall the car but it won't wreck anything... more of a pain for you. When you car doesn't pass emissions (in states where it's required) usually you change that along with some basic tune up items like O2 sensor, plugs, and other little things.

 

- RedFox340

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I have already posted about this and its really bothering me. I went to the library and was browsing through the chiltons and haynes and I came across a haynes for a 1995-2001 Montes, Luminas, And Impalas. It went through everything in detail except for one little section on the 3.4 DOHC and it told nothing of the PCV valve. Nothing on Plugs and Wires or any tune-up stuff. I wanted to replace my PCV but I have no idea where it is?

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Combustion gases that blow by the rings have to go somewhere. If the crankcase was sealed, the pressure would blow out seals and there would be oil leaks.

 

Up until the 1960s, a "draft tube" from the crankcase to down near the road would use the breeze under the car to suck the gases out of the crankcase. A breather would let fresh air into the crankcase. Small engines like lawn mowers, still use this system today.

 

To reduce emissions and oil drips, PCV systems were developed for automotive engines, to re-burn crankcase gases. When starting and idling, the PCV valve restricts crankcase gas flow to the intake. A clogged PCV valve can result in oil leaks, oil in the air cleaner, and sludge buildup in the engine. Leaks in the hose are vacuum leaks and cause idle and running problems.

 

Quad-4 motors use an oil/air separator that returns oil to the crankcase and gases to the intake.

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I am having a problem with my pcv comming off when I start my car making a backfire and the pcv is only a month old it did this with the previous pcv

 

Is it on backwards? A PCV only lets flow of one direction happen. Perhaps an easy fix... ya'?

 

- RedFox340

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