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Does a PCV valve go bad ??

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Old 07-20-2007, 10:04 PM   #1
Jims1988C4
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Default Does a PCV valve go bad ??

what are the symptoms if it does and what does it do ?? Hope these are not stupid questions,
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Old 07-20-2007, 10:39 PM   #2
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Typically a PCV valve fails by getting enough crud in it to prevent it from operating.

You can check it by removing it from the valve cover and shaking it. If it rattles, then it's OK. Take the time to give it a visual inspection. They are usually very trouble free components.

Steven
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Old 07-20-2007, 10:40 PM   #3
Midnight 85
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The PCV is a one way valve, you should be able to blow into the hose end only. They do definitely go bad from getting all gunked up inside. They're so cheap they should be changed about once a year anyway.
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Old 07-21-2007, 06:51 AM   #4
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PCV valve=positive crankcase ventilator and does just that. Ventilates vapors from the crankcase. Remember the cars from the 60's that ya always seen the 3/4" tube sticking down to the bottom of the engine and would bellow smoke when they were all gunked up? This replaced that crakcase pressure relief. If gunked to the point of not working (actually is a check valve) rough idle will happen as this works on your vacuum system. If it does not rattle it can be cleaned with injector spray. Blow in the engine side of the valve, should let air thru. Suck on the engine side of the valve and it should block off tight. Not an expensive item but also rarely fails just needs cleaned from time to time.
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Old 07-21-2007, 06:57 AM   #5
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Quote:
You can check it by removing it from the valve cover and shaking it. If it rattles, then it's OK. Take the time to give it a visual inspection. They are usually very trouble free components.

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Old 07-21-2007, 07:30 AM   #6
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Quote:
Originally Posted by OldCorvetteFan View Post
Typically a PCV valve fails by getting enough crud in it to prevent it from operating.

You can check it by removing it from the valve cover and shaking it. If it rattles, then it's OK. Take the time to give it a visual inspection. They are usually very trouble free components.

Steven
It should also apply vacuum to your finger when you touch the bottom of it with engine on, and you should hear it "click" at the same time.
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Old 07-21-2007, 01:52 PM   #7
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Quote:
Originally Posted by OldCorvetteFan View Post
Typically a PCV valve fails by getting enough crud in it to prevent it from operating.

You can check it by removing it from the valve cover and shaking it. If it rattles, then it's OK. Take the time to give it a visual inspection. They are usually very trouble free components.

Steven


Oil Can Henry's and the like will try to sell you one of these and an air filter about every time you change oil. Engines run so clean now the PCV valve seems to last forever. If it rattles when shaken as this poster says and with the engine running, remove it from the valve cover and it pulls a good vacuum, as another poster says, its works. That's all it does. I replace mine once every million years, or when the vacuum hose and grommet that the PCV valve attaches to rots away, which ever comes first. Then it's a 'while I'm there' type replacement, not because it's shot. Don't think I've actually seen a gunked up PCV valve since the 70's, and that would have been on 60's cars. Even then it's most likely an indication that the rings and/or valves are shot.

PCV= Positive Crankcase Ventilation. Pretty self explainitory. Crankcase gasses used to be vented to the atomosphere through a draft tube. Since the late 50's or so, these gasses are vented internally through the PCV system.

A symptom of a non functioning PCV valve would be oil accumulation at where ever the breather for the PCV system is, typically in the air cleaner housing. On a carborated vehicles, the idle mixture will be rich.

jmo

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Old 07-21-2007, 07:45 PM   #8
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Thanks guys,I just replaced it just because,just because IV replaced most every thing else under the hood...Thanks again.
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Old 07-21-2007, 08:37 PM   #9
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Quote:
Originally Posted by Jims1988C4 View Post
Thanks guys,I just replaced it just because,just because IV replaced most every thing else under the hood...Thanks again.
did anything change after you changed it ?
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Old 07-21-2007, 11:32 PM   #10
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Quote:
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did anything change after you changed it ?
Yeah - his wallet was lighter, and the car runs faster now because of less weight!

Steven
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Old 07-21-2007, 11:38 PM   #11
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Yeah - his wallet was lighter, and the car runs faster now because of less weight!

Steven
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Old 07-22-2007, 12:08 AM   #12
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My new one (probably chinese) didn't fit tight in the hole, so I put some High Temp silcone aroung the diameter of it and let it set, then slid it in the next day and fit nice and snug. Just a suggestion.
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Old 07-22-2007, 01:51 PM   #13
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It's easy enough to just clean it to.
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