# PCV/Catch device vs. Breather filter Pros? Cons? Explain please.



## 83Rabbit (Dec 15, 2000)

Ok, I was wondering about the breather element mod that many people use to stop the back flow of oil into the intake tube.
I want to know what the pros and cons are of using a breather style filter and what do you do to install it? Block off the hole in the intake tube where it connects and hook up a breather filter to where the PCV hose comes out of the head?
What are any negatives besides those fumes being released into the engine bay now instead of back into the intake? Furthermore, how does this stop oil from going back down the intake? No vacum to suck it up from its start at the valve cover?
Any pictures of the assemblies, custom or otherwise?
Diagram of exactly how PCV works?
Thanks http://****************.com/smile/emthup.gif


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## DonL (Feb 28, 1999)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (83Rabbit)*

Bump, since I've been curious about something, too.
Is there a block-off plate available for the crank vent "box", or are they usually just plugged in some way, like with an old temp sensor?


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## 69523 (Sep 12, 2002)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (83Rabbit)*

i've had that pcv apart and its really just a tee. there is a diaphragm in it but it doesn't provide a positive vent. i'll look for pictures.
i think using a catch can would be best to keep the oil out of the intake. 
i don't know about a filter, seems like a bad idea to me as oil would saturate the element. there is a thread where some people used an inline pneumatic oil dryer.
you can block off where the oil drains into the block, but you still want some kind of vent at the crankcase, you don't want excessive pressure to build up.


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## soccergk (Apr 19, 2005)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (83Rabbit)*

can anyone else share their 2 cents?


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## tdogg74 (Mar 1, 2002)

This is all you need to know....
...you put one of those little filters on the end of your PCV valve, and the inside of your cabin is going to STINK. The intake for the the HVAC is located in the rain tray about two foot from where that thing is pointing.


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## vr6killer (Aug 31, 2004)

ive had the breather filter mod forever and my motor is fine and there is no backup of oil or saturation or anything, its fine. Go for it!


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## 94jetta~~ (Feb 22, 2002)

*Re: (tdogg74)*

I have a filter on the PCV valve because i blocked off the hole in the block because the pipe broke. It's still connected to the intake though. No problems yet and no smell in the cabin either


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## gltuner (Oct 7, 2004)

I had something similar done to my car with the breather filter. I think my PCV assembly was bad as after 3 weeks of driving (~ 700 miles a week), the filter element was soaked. I was concerned about oil getting to the timing belt and causing the belt to swell/weaken and fail, so I replaced the breather with a hose connected to the intake stream.
My $.02 on it, do the catch can mod, it removes one more element from causing the failure of parts.


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## punisher89 (Oct 11, 2002)

*Re: (gltuner)*

Bump b/c I have this same dilemma now and I need to see pics for my retarded ass.


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## ABF Jeff (Nov 16, 2005)

*Re: (punisher89)*

I have a little filter on the valve cover, and the breather tube from the bottom is piped into the stock pcv valve. It seems to work well for ventilation, but you *can* smell it at a stop light.


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## mk2.slow (Oct 17, 2003)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (83Rabbit)*

I know that people have run breather filters successfully but, I really don't like the idea of no vacuum on the pcv system. The reason you see breathers on V8s and other older cars is because the pcv system is hooked up to manifold vacuum and draws air THROUGH the breather at idle. Originally the system was plumbed to the ported side of the air cleaner. At open throttle, manifold vacuum drops and the system vents through the breather or into the air cleaner. At partial throttle, when manifold vacuum is higher, the system would vent directly into the intake manifold. Hope that made sense.
That being said, the 2.0 pcv system was never hooked up to manifold vacuum. The only time you get crankcase scavenging is when the throttle is open a good deal. This is when you need it most, anyway. A properly operating pcv system will help your oil seals perform better and supposedly is better for your rings, too. 
It seems to me that most of the oil comes from the lower crankcase vent.  I could see how a blockoff plate could be a good idea. I would, however, leave the valvecover vent hooked up to the intake. Blowby in the crankcase will make it up to the valve cover through the oil drains.


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## eurosportgti (Jan 15, 2003)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (mk2.slow)*

my boy is runnning a catch can on the block and a breather on his 2.0t and it works greats


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## R (Oct 28, 2000)

*Re: PCV/Catch device vs. Breather filter Pros? Cons? Explain please. (mk2.slow)*


_Quote, originally posted by *mk2.slow* »_. A properly operating pcv system will help your oil seals perform better and supposedly is better for your rings, too. 
It seems to me that most of the oil comes from the lower crankcase vent. I could see how a blockoff plate could be a good idea. I would, however, leave the valvecover vent hooked up to the intake. Blowby in the crankcase will make it up to the valve cover through the oil drains. 

Very true, not to mention we need more oil vapors vented into the air we breath, NOT!
TT has a block off plate for the lower opening as part of the aba swap into 1.8 using the 1.8 head etc..
The bottom vent is the problem. Block that off (I used a big rubber plug where the plastic tube connected). Then get a pcv valve of your choice and grommet to fit opening in valve cover. Plumb that to intake and your not only environmentally responsible but your pcv system will work as it should.
Rick


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