Bad PVC Valve???

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
Yes, the valve can be tested.. Remove it from the valve cover and close off both inlet ports with your fingers. Now apply vacuum to the outlet port. You should be able to hear and feel the diaphragm being pulled down. While maintaining vacuum, remove both fingers from the inlet ports. The vacuum should hold. If the valve's interior is particularly dirty, it may only hold vacuum for a few seconds, but it should hold at least briefly.
 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I've always wondered if these could be opened, to have some type of filter material added.

-Todd
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
You can open them up but stuffing them with filter material would prevent the valve from functioning properly and defeat its purpose.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Thank you... now I can stop wondering, lol.

Now I'm wondering if putting a filter inline would help keep the intake cleaner. I used to use a Wix fuel filter that had 1/2" barbs, on my gassers. I think I still have a couple floating around.

-Todd
 

mustangmarty

Veteran Member
Joined
Nov 9, 2016
Location
Central Texas
TDI
1996 Passat Wagon TDI
Yes, the valve can be tested.. Remove it from the valve cover and close off both inlet ports with your fingers. Now apply vacuum to the outlet port. You should be able to hear and feel the diaphragm being pulled down. While maintaining vacuum, remove both fingers from the inlet ports. The vacuum should hold. If the valve's interior is particularly dirty, it may only hold vacuum for a few seconds, but it should hold at least briefly.
Ok, the inside is very sooty, oily, dirty inside all three ports. When I do that test, I can hear the diaphragm pulling down. When I release the intake ports, there is barely a slight restriction of air flow which becomes unrestricted airflow after only a half a second. My vacuum source was just me sucking on the outlet port though. Will soaking it in soapy water help things?
 
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KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Why are you worried about it functioning? It's not there to keep blowby oil out of the intake. It never closes in normal operation.

What I've read is that it's to keep the engine from running on oil if you turn the car over.
 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
With egr delete, you wouldn't be doing a CCV delete. At least, I wouldn't...

-Todd
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
Why are you worried about it functioning? It's not there to keep blowby oil out of the intake. It never closes in normal operation.

What I've read is that it's to keep the engine from running on oil if you turn the car over.
Actually, it won't prevent the start of a runaway when upside down, although it will partly restrict the amount of oil consumed once the runaway is really cranking.
Its primary purpose is to prevent the onset of a runaway caused by an equally rare event; a severely restricted or plugged air filter or snow screen. Its activated by very high negative pressure in the intake tract caused by either the aforementioned tract restriction or a runaway already in progress. Unfortunately it won't stop the active runaway; crankcase pressure is high enough under these circumstances to partially overcome the vacuum-activated valve, but it will prevent onset of a runaway under the less severe circumstances of a restricted intake.
 
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