PCV behavior during boost leak test...Is my PCV Valve bad?

[4gfun]

I am trying to verify that my PCV valve is bad. I am not exactly sure whether or not I got this right though.

I did a boost leak test by pressurizing the turbo inlet with a compressor and the hose going to the PCV hisses away if it is not connected to the PCV. If I remove the PCV from the valve cover, the hiss is not nearly as loud but the PCV does let air out of the end that is opposite to the hose (The part that goes into the valve cover) of course that end is out of the valve cover during the boost leak test so I can observe it.

Do I have a bad PCV valve?

Thanks!

 

[1995gsx20g]

im having a hard time figuring out what your trying to say so ill give you a little rundown..

the pcv should not allow boost pressure to go from the IM to the VC.
the pcv should allow air to go from the VC to the IM.

if you wanna know any more Calan has spent a good amount of time doing a full legit write up on the subject.
http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html#post152294004

 

[4gfun]

im having a hard time figuring out what your trying to say so ill give you a little rundown..

the pcv should not allow boost pressure to go from the IM to the VC.
the pcv should allow air to go from the VC to the IM.

if you wanna know any more Calan has spent a good amount of time doing a full legit write up on the subject.
http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html#post152294004

Thanks for the info. I already took a look through Calan's link. Thanks for trying to understand what I am trying to say. So the end of the PCV valve that is not connected to the VC ultimately goes to the IM? If that is the case, I can make a logical deduction without making this complex.

 

[9!'clipseDOHC]

Thanks for the info. I already took a look through Calan's link. Thanks for trying to understand what I am trying to say. So the end of the PCV valve that is not connected to the VC ultimately goes to the IM? If that is the case, I can make a logical deduction without making this complex.

The PCV hose runs from the Intake Manifold (IM) to the Valve Cover (VC) with the PCV valve screwed into the valve cover.

PCV valves are known to leak. As it is mentioned in Calan's tech article, it is a good idea to add on of these 3/8 check valves inline with the PCV valve.

Hope this helps!

 

[4gfun]

The PCV hose runs from the Intake Manifold (IM) to the Valve Cover (VC) with the PCV valve screwed into the valve cover.

PCV valves are known to leak. As it is mentioned in Calan's tech article, it is a good idea to add on of these 3/8 check valves inline with the PCV valve.

Hope this helps!

So the PCV valve leaking is unacceptable? Forgive my ignorance. Also, isn't getting a new OEM PCV valve supposed to be enough?

Thanks for your thoughts.

 

[1995gsx20g]

So the PCV valve leaking is unacceptable? Forgive my ignorance. Also, isn't getting a new OEM PCV valve supposed to be enough?

Thanks for your thoughts.

pcv valve leak going from the IM to the VC is no good.


a new oem pcv valve may fix it for a little while but modified cars tend to make them leak faster so a check valve lets us not replace the valve every month.

 

[4gfun]

pcv valve leak going from the IM to the VC is no good.


a new oem pcv valve may fix it for a little while but modified cars tend to make them leak faster so a check valve lets us not replace the valve every month.

Thanks all, check valve it is...once I verify that the boost leak isn't a BIG BUCK $$$ situation!

 

[FwDdSm]

One quick way to check to see if the PCV valve is working correctly is to blow into it on the end and see if air comes out the other side. If so, then more than likely it's bad. It is best to go with an oem PCV valve.

 

[4gfun]

One quick way to check to see if the PCV valve is working correctly is to blow into it on the end and see if air comes out the other side. If so, then more than likely it's bad. It is best to go with an oem PCV valve.

I did that and it seemed fine, but it behaves differently under pressure. This is why I made that confusing first post .

 

[toofast82]

As said, blow through the pcv for a quick check.
In my experience, you need to use an OEM pcv valve as the "parts store" ones tend to leak in a short period of time if not right from the beginning.
I'd recommend looking into a properly setup catch can and check valve system

 

[steve]

One quick way to check to see if the PCV valve is working correctly is to blow into it on the end and see if air comes out the other side. If so, then more than likely it's bad.

All this test will do is tell you if you have a really bad PCV valve.

You have to check them under at least your boost pressure and I doubt anyone here can generate 12-20+ psi with their lungs. You need an air compressor to test the sealing of the valve under pressure.

Nothing should pass through the valve when applying pressure from the barbed end toward the threaded end. If it does it's going to be a boost leak in a running car and blow oil vapor into the intake.