PCV Valve Brand / Function

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
I bought a UROParts hockey puck of the same exact part number as the original VW one that I took off, and it doesn't fit into the valve cover grommet, the lip of it is fatter and also 27 thousandths wider in diameter, which is enough for it not to fit.

Anyone have luck with aftermarket, or is the pricey VW one a must?
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
I got rid of the puck ages ago. Lower ccv crank block off plate too. Just use a copper 3/4 street 90* with (street side fits nicly into the grommet) a pex male solder to barb in 3/4. Rubber hose or vinyl braided from pex fitting to the turbo intake pipe. Costs about $4. I highly suggest you add a $20 proper oil vapor catch can. I tapped a hole into the block off plate at the crank ¹/4 NPT and ran the bottom of the catch can to it to drain. The puck literally does nothing after a while.
 

Steve Addy

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Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Obviously URO doesn't make anything, they just repackage what others make. Having said that it seems that they tend to pick the lowest possible quality available and I try to avoid them unless there are no other options.

I think my rear beam axle bushings I bought were URO. They have held up good, then again it was a new suspension when I installed them, which makes a difference. I may also have purchased a URO cooling system flange too at some point.

I would avoid them unless there's no other option for you.

Steve
 

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
I got rid of the puck ages ago. Lower ccv crank block off plate too. Just use a copper 3/4 street 90* with (street side fits nicly into the grommet) a pex male solder to barb in 3/4. Rubber hose or vinyl braided from pex fitting to the turbo intake pipe. Costs about $4. I highly suggest you add a $20 proper oil vapor catch can. I tapped a hole into the block off plate at the crank ¹/4 NPT and ran the bottom of the catch can to it to drain. The puck literally does nothing after a while.
Doesn't the puck regulate crankcase pressure? Pretty sure I have too high of pressure in there, looks like the pcv I have has a collapsed diaphragm. Getting leaks out of the 3 valve cover bolts, oil filler cap, and where the breather hose meets the puck, and where the hose from the puck meets the intake. Would sure like to add a catch can in there, it's on the list.
 

Steve Addy

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Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Doesn't the puck regulate crankcase pressure? Pretty sure I have too high of pressure in there, looks like the pcv I have has a collapsed diaphragm. Getting leaks out of the 3 valve cover bolts, oil filler cap, and where the breather hose meets the puck, and where the hose from the puck meets the intake. Would sure like to add a catch can in there, it's on the list.
You might benefit from replacing the rubber bits for the valve cover hold downs, those get very stiff over time due to age and oil exposure.

I have replaced them on my cars.

Steve
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
The puck is just a bigger chamber that holds a medium that resembles a foam sponge like thing that tried to stop oil droplets from going past and only letting oil vapor going though. It does this for the lower beather hose and the upper valve cover area (obviously). The lower breather was added for some reason but it's not needed. There are other engines with this block that have them blocked off from factory. Most of it was all an emissions attempt by VW. I've been running it blocked off with high hp and high revs with no issues what so ever with no catch can. Just a pipe I described above.
It has nothing to do with regulating anything. It eventually let's oil droplets fly by, probably after a few 10tousand miles from factory. You're actually supposed to replace it with every oil change but it was never made an official service item when VW did emission compliance.
Just do what I said above. Or buy oem parts. The lower breather is $$$ and always leaks once disturbed.
 

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
The puck is just a bigger chamber that holds a medium that resembles a foam sponge like thing that tried to stop oil droplets from going past and only letting oil vapor going though. It does this for the lower beather hose and the upper valve cover area (obviously). The lower breather was added for some reason but it's not needed. There are other engines with this block that have them blocked off from factory. Most of it was all an emissions attempt by VW. I've been running it blocked off with high hp and high revs with no issues what so ever with no catch can. Just a pipe I described above.
It has nothing to do with regulating anything. It eventually let's oil droplets fly by, probably after a few 10tousand miles from factory. You're actually supposed to replace it with every oil change but it was never made an official service item when VW did emission compliance.
Just do what I said above. Or buy oem parts. The lower breather is $$$ and always leaks once disturbed.
So just to make sure, the puck I have has a spring loaded plastic piece in it that has a plastiicy-rubbery diaphragm sandwiched in between it that I believe holds air and does not absorb anything. Engine vacuum pulls the valve closed (to not let boost pressure into crankcase?). Crankcase pressure keeps the valve open to allow the vapors to go to the intake. Does it not?

The lower breather is simply a pipe, correct? I always thought it was an oil-return pipe, to let any oil that condenses in the puck to fall back in the engine, but do see they are sold as breather pipes. The first and last time I let a "VW specialist" work on my car, they put a block off plate on the block where the breather tube comes out, but left the breather tube in place, which they broke and so had a big crack in it, and oil would heavily leak to the ground from there - coming from nowhere else but the puck up top. I replaced the pipe (this was a few years ago now) with a cheap aftermarket one and it is still leak free, except now recently a drip forms where it connects to the puck, along with other areas starting to drip.

I like the idea of getting rid of the puck, just want to make sure and understand why. Thanks for the info.
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
I dont see any vacuum lines or spring loaded anything on that part number. Looks identical ot my ahu. As I though you had as well.either way.
 

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
Yea there's no vacuum lines, and pictures won't show what's on the inside, but mine and also the UROParts one has the plastic valve, spring, and rubbery diaphragm in it. If you plug the two side holes and suck on the valve cover outlet, the valve closes, and when the 'vacuum' is released, the spring pushes the valve back to the top of the puck in open position. I figured that during boost, the engine pressure is negative (i think?) and the vacuum of negative pressure closes that valve so boost pressure does not pressurize the engine. I figured the purpose of the diaphragm is only to provide an air seal for the plastic valve. Compared to the new UROparts one that didn't fit, my diaphragm looks deflated and the valve operates slower, as in it does not respond as quickly to vacuum. I cleaned it out good and still the same.

I would think the AHU and 1Z would use the same one, and if you aren't using one and are not having pressure issues, I am intrigued. Would rather not drop $90+ on a new oem hockey puck.
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
Like I said, these blocks have many variations. But they all do the same thing basically.
I've cut mine open, just a filter like sponge inside. Can you post a picture? What is the part number of the part you removed?
If any of these engines had pucks that had a vacuum control, it would be regulated by something, these cars run on boost to the ECU. Vac is only for breaking and HVAC control and most of that is cables.
Vacuum on these has nothing to do with vacuum of the engine.
Maybe its ran on boost but that would not make any sense. I'm very curious what's going on and how its controlled. I've given my input and please. Take it with a grain of salt. I'm mostly fimilure with these engines but I'm just a hobbyist shade tree mechanic who knows too much for my own good.
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
100% correct. how could i forget.
i have never heard of a 1z or AHU use any control via boost or vacuum for the CCV puck.
there could be a check valve in there, maybe its right for your engine but im still sceptical. I ran 32PSI on my set up and had basically the entire thing a dete other than the one pipe form the valve cover. never once had the dip stick pop out or leaks at the 3 bolts or the gasket. if its leaking like you say, there are other issues, put a washer under the bolts to make it compress a bit more. thin washers. that or replace the rubber parts. easy fix.
 

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
I spent 20 minutes trying to get it to fit in there. I wanted it to fit, but it didn't. Was worried about breaking something. The OEM one fits in tight.



It might not look like much, but the URO lip is higher and is 27 thousandths of an inch wider, which is enough for it not to fit. I dunno, maybe my grommet is oversized, but the fact the OEM fits snug and does not leak says something. But I'll look into pulling it off and trying to get a picture of its innards.
 

Benjamis

Active member
Joined
Jan 17, 2021
Location
Cincinnati, Ohio
TDI
1996 Passat TDI Wagon 1Z 306k miles
It would fit into the rubber but it would not squeeze through when it gets to the valve cover. I pulled the grommet off and could fit it fully into the grommet, but with the grommet installed, it will not squeeze through. I was pushing down the whole car trying to push it in. It's a piece of plastic though so I didn't want to break it. I already returned it, thankfully autozone accepted the return even though it was opened.
 

Steve Addy

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Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I spent 20 minutes trying to get it to fit in there. I wanted it to fit, but it didn't. Was worried about breaking something. The OEM one fits in tight.

It might not look like much, but the URO lip is higher and is 27 thousandths of an inch wider, which is enough for it not to fit. I dunno, maybe my grommet is oversized, but the fact the OEM fits snug and does not leak says something. But I'll look into pulling it off and trying to get a picture of its innards.
It's a tight fit anyway even with the OEM, and if your grommet at the valve cover is old and hardened that would make it even worse, but that's one reason I don't really trust the URO stuff, the fit can be questionable.

Steve
 

Mongler98

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Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
Who's your vendors?
Not mine, vendors here at our forums like ID parts and GAP (GERMAN AUTO PARTS) ECS tuning and so on. Plenty of good quality parts to be had. God forbid you have to do to a dealership, no serisoulh stay away from box stores like autozone ect...... for your VAG parts.
 
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