is pcv supposed to be air tight?

[King_berald]

I have 2 replacement pcv valves for an ls1. part number pcv-001.
1 is brand new , the other was on the car. both are leaking air if i blow through them like a controlled leak.
the old genuine one i have is airtight sometimes. Is pcv-001 the correct part for an ls1? is it supposed to have a controlled air leak or something? i have vacuum issues.
i also have pvc-036 which was specified for the l67. It is airtight.

 

[King_berald]

I can confirm that running the old genuine pcv has sorted my vacuum issue out.
But very confused. Pcv001 is the part number specified for ls1 and 5.0.
i have read that gm had an alternative version that was a different design that actually does have a controlled air leak for low vacuum cam applications. I believe it is discontinued though. Hoping someone has some insight?

 

[Immortality]

The PCV is a controlled air leak. The PCV system is there to flush the crank case with clean air and evacuate combustion gases that make it there.

The PCV is also basically a one way valve so it will allow air flow in one direction but block it in the other. I believe it also does this in the case of a backfire, the last thing you want is the backfire going into the crank case via the PCV valve.

 

[King_berald]

The PCV is a controlled air leak. The PCV system is there to flush the crank case with clean air and evacuate combustion gases that make it there.

The PCV is also basically a one way valve so it will allow air flow in one direction but block it in the other. I believe it also does this in the case of a backfire, the last thing you want is the backfire going into the crank case via the PCV valve.

i was also under the impression that it was supposed to be a 1 way valve. pvc-001 which is the aftermarket replacement for the ls1 doesn't seal at all. it restricts airflow but doesn't seal completely. I thought maybe i had a faulty valve but they're all like that.
If someone can confirm that its supposed to be a complete seal, ill run the pcv-036 which is identical but actually makes a seal.