Oil breather valve/PCV, how does it work? & can you test

reluctantartist · Post by **reluctantartist** » Wed May 20, 2009 6:10 am

I have an 1982 vanagon so our breather valve just plugs in to the engine. But the valve looks like it has a diaphragm the other PCV I have experiance with do not have a diaphragm. Is there some way to test this? Is it a one way valve?

Thanks

Gypsie · Post by **Gypsie** » Wed May 20, 2009 8:41 am

Do you have any pix?

reluctantartist · Post by **reluctantartist** » Wed May 20, 2009 11:26 am

Here is a link to the part...http://www.germansupply.com/home/custom ... 348&page=7

Gypsie · Post by **Gypsie** » Wed May 20, 2009 1:25 pm

Just wanted to confirm tyhat we are talking apples to apples.

I believe it is a one way valve. I haven't felt the need to check to see if mine only flows one way. I have only been concerned with assuring that the oring eaals for cleanliness and vacuum concerns.

Are you having symptoms or just expanding your knowledge base?

I am interestedto know if it is one way as well

I have always considered it to be a PCV valve.

Colin, Hal, Jasan, anyone?

airkooledchris · Post by **airkooledchris** » Wed May 20, 2009 1:42 pm

quoted from a post 10cent made over at TS that I had bookmarked on this topid:

"There is a diaphragm that is supposed to block the large breather outlet at high intake vacuum, by being pulled downward against a weak coil spring. There is a small orifice at the bottom of the elbowed outlet tube below it that would always allow a very small flow to get thru. The rest of it is just a baffled tower to allow condensed vapors to drain back to the sump, a liquid separator.

The problem is the diaphragm rots away, like the one in the photo, leaving the thing wide open at all times. Also, it's hard to see where any air is allowed above the diaphragm so it can move downward when there is a large pressure difference vs. atmosphere anyway. "

Gypsie · Post by **Gypsie** » Wed May 20, 2009 2:24 pm

=D> =D>

Thank you.

reluctantartist · Post by **reluctantartist** » Wed May 20, 2009 7:49 pm

Hmmm.. I know there is a tiny hole on top of these things so that means that it would cause a slight vacuum leak. What are we supposed to do? I doubt any of these things are intact anymore. And no I am not really having problems with my vehicle but I am trying to chase down anything that would affect its running before it is a real problem.

Post by **Amskeptic** » Thu May 21, 2009 7:34 am

reluctantartist wrote:Hmmm.. I know there is a tiny hole on top of these things so that means that it would cause a slight vacuum leak. What are we supposed to do? I doubt any of these things are intact anymore. And no I am not really having problems with my vehicle but I am trying to chase down anything that would affect its running before it is a real problem.

Type 4 engines had open breathers on all carbureted versions. You can run a FI engine with an open breather so long as it is not a tired engine, and you check your mixture through the range.
Colin
(the little hole is to allow atmospheric pressure to act on an intact diaphragm, IIRC)

reluctantartist · Post by **reluctantartist** » Thu May 21, 2009 8:11 am

So that means I need to plug up the hole on my breather. I know the diaphragm is not intact.

I just found a long discussion on this in the vanagon forum and they concluded this needs to be working or an equivalent restricter set up needs to be in place to consistently meter the gases over time like the diaphragm does intermittently. This may be the last piece to my slightly high idle puzzle (the extra 25-50 rpms when I hook up the digital idle stabilizer). Could you use another oil breather cap/pcv from an American vehicle?

Thanks

Itinerant Air-Cooled

Itinerant Air-Cooled

Oil breather valve/PCV, how does it work? & can you test

Oil breather valve/PCV, how does it work? & can you test