Testing PCV system.....is this a way?

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I was told to put a rubber glove ove the oil fill hole with the engine running and if it sucks the glove in that it means the PCV is working. If it inflates the golve it is not functioning. Is this correct?
 
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The rattle test has been the way for years. But some of the new valves are a little different since they are spring loaded. In kia/hyundai's you now remove the valve and use a stick to see if valve moves when pressed. If it does not it needs to be replaced, it may still rattle since it has 2 springs.
 
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"I was told to put a rubber glove ove the oil fill hole with the engine running and if it sucks the glove in that it means the PCV is working. If it inflates the golve it is not functioning. Is this correct? " I would say no. The pressure in the crankcase is usually going to be positive so the glove will always blow out. The PCV valve is a one way. Gas only goes out of the valve cover towards the intake manifold. It should only move when there is pressure from the valve cover side, not if there is only a vaccum from the intake side. If you're in doubt, spend the three bucks to replace it.
 
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Don't forget that a PCV could have weak springs or build up inside that is preventing it from working properly. It may still suck a glove in and may still rattle when shaken, but could still be defective or not operating properly in both cases. I would just replace it regularly if it's not the electronic type, because they are cheap and it's cheap insurance but does so much for your engine and could be a headache if it fails on you. \:\! Always use an OEM, don't use aftermarket brands. Most of these aren't 100% the same as the original and can cause problems. ;\)
 

Chris B.

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 Originally Posted By: bepperb
"I was told to put a rubber glove ove the oil fill hole with the engine running and if it sucks the glove in that it means the PCV is working. If it inflates the golve it is not functioning. Is this correct? " I would say no. The pressure in the crankcase is usually going to be positive so the glove will always blow out.
Mine was sucked in,
 
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QCA, IA
 Originally Posted By: bepperb
"I was told to put a rubber glove ove the oil fill hole with the engine running and if it sucks the glove in that it means the PCV is working. If it inflates the golve it is not functioning. Is this correct? " I would say no. The pressure in the crankcase is usually going to be positive so the glove will always blow out. The PCV valve is a one way. Gas only goes out of the valve cover towards the intake manifold. It should only move when there is pressure from the valve cover side, not if there is only a vaccum from the intake side. If you're in doubt, spend the three bucks to replace it.
The only situation I can think of where the glove would "blow out" at idle would be if both the inlet and outlet of the PCV system were blocked or you had very, very severe blow by, basically worst case scenario. Generally there should be very little pressure at all, the inlet is open to atmosphere, after all.
 
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The rattle test is not valid, like StevieC said. AT the line to the PCV, you should have full manifold vacuum. As for testing the PCV valve itself, it is tough. Our best bet is to make sure it is very clean inside and has no leaks. Sealing faces wear, and springs [if any] lose tension. If you get a new one, get the best you can, not a 'white box' cheapo.
 

Chris B.

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 Originally Posted By: Scimmia
 Originally Posted By: bepperb
"I was told to put a rubber glove ove the oil fill hole with the engine running and if it sucks the glove in that it means the PCV is working. If it inflates the golve it is not functioning. Is this correct? " I would say no. The pressure in the crankcase is usually going to be positive so the glove will always blow out. The PCV valve is a one way. Gas only goes out of the valve cover towards the intake manifold. It should only move when there is pressure from the valve cover side, not if there is only a vaccum from the intake side. If you're in doubt, spend the three bucks to replace it.
The only situation I can think of where the glove would "blow out" at idle would be if both the inlet and outlet of the PCV system were blocked or you had very, very severe blow by, basically worst case scenario. Generally there should be very little pressure at all, the inlet is open to atmosphere, after all.
So in my case where the glove was sucked, is that normal? A good thing?
 
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QCA, IA
If it was just sucked in a little, then yes, that's normal. The inlet that's open to atmosphere generally isn't that big, so there's going to be some restriction there. If it sucked it in a lot, then you have a problem, either the PCV valve is letting way too much through, or the inlet is blocked.
 
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Alabama, USA
 Originally Posted By: StevieC
Don't forget that a PCV could have weak springs or build up inside that is preventing it from working properly. It may still suck a glove in and may still rattle when shaken, but could still be defective or not operating properly in both cases. I would just replace it regularly if it's not the electronic type, because they are cheap and it's cheap insurance but does so much for your engine and could be a headache if it fails on you. \:\! Always use an OEM, don't use aftermarket brands. Most of these aren't 100% the same as the original and can cause problems. ;\)
+1
 

Chris B.

Thread starter
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3,542
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Colorado
 Originally Posted By: Scimmia
If it was just sucked in a little, then yes, that's normal. The inlet that's open to atmosphere generally isn't that big, so there's going to be some restriction there. If it sucked it in a lot, then you have a problem, either the PCV valve is letting way too much through, or the inlet is blocked.
It was just a little.....just made the glove collaps on itself.
 
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Chicago Area
Yes, that is a good sign and is normal. But it is inconclusive about the condition of the valve. They are pretty simple - try a good cleaning or spend $6.
 
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