Classic Mustangs (Tech) Technical discussions about the Mustangs of yester-year.

Noisy PCV Valve

Old Jul 13, 2010 | 12:25 PM
  #1  
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unit91
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Unhappy Noisy PCV Valve

PCV valve sounds like a Singer sewing machine. You can hear it rattling with the hood closed. Sounds like valves pinging but when I pull the valve out of the valve cover the noise stops. Does this noise indicate a problem with the PCV valve? Also when I pull it out I see some very faint smoke or steam - can't tell which. Radiator not losing water.
Old Jul 13, 2010 | 02:08 PM
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they are like 2 bucks pick a new one up and see if its better.

The "steam" is probably just crank gasses and is normal

-Gun
Old Jul 13, 2010 | 02:23 PM
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I put a new one in. Same thing. Plenty of vacuum at the end of the valve though. NAPA parts guy said the original equipment PCV had another part that the PCV fits into, then that assembly fits into the valve cover. ?????
Old Jul 13, 2010 | 02:52 PM
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If you take the valve out and place your finger over where it fits into do you feel any kind of pulse.

I dont think there should be any pulse of air in a normal situation but im wondering if that's whats causing the valve to make noise...

-Gun
Old Jul 13, 2010 | 03:34 PM
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When I pull the PCV and put my finger over the end of it there's steady suction and no noise/rattle, and the engine starts to stall.
Old Jul 13, 2010 | 04:35 PM
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Put the PCV back in and hook it back up.
Then take your breather cap off and see if the noise goes away. If so, replace your breather cap and/or filter.
If your breather cap is bad or clogged the air can't get into the crankcase to replace
the air/gasses sucked out by the PCV and it won't operate correctly.
Old Jul 13, 2010 | 06:30 PM
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the older style breather caps can be washed out in some gas and reused.

does it stall or just drop the idle speed a little?
Old Jul 14, 2010 | 06:19 AM
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Originally Posted by 1971mach1
Put the PCV back in and hook it back up.
Then take your breather cap off and see if the noise goes away. If so, replace your breather cap and/or filter.
If your breather cap is bad or clogged the air can't get into the crankcase to replace
the air/gasses sucked out by the PCV and it won't operate correctly.
yep. i'd try that as well.

the PCV valve seems to constantly open and close at idle, which is perfectly normal. However it shouldn't make much of a noise.
Old Jul 14, 2010 | 02:16 PM
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I had the same problem. I asked for a PCV valve for my car. It had to ports on it. I didn't want one with 2 ports so I bought one the profile I wanted. That PCV valve rattled something awful. PCV valves are basically a sprung check valve. I had one with the incorrect spring rating. I bet yours is incorrect also. It can vary on the brand but Fram PCV springs are rated with letters, A,B etc. Get a PCV for your car. Check the spring rating and buy the one you want with the same spring rating. You may not be able to depending on the PCV valves carried by your local parts supplier. Good luck.
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