As many of you know, we have this dumb thing on our car called the PCV Valve. It is stupid, fails often, and causes numerous different issues when it goes bad ranging from loss of boost to whistling noises to poor idle speeds etc... All the while, never really doing the job it was intended for.
Here is said PCV:
For a little info on what we are dealing with here:
The blowby vapors that end up in an engine's crankcase contain moisture as well as combustion byproducts and unburned fuel vapors. The crankcase is sealed to prevent the escape of these gases into the atmosphere, but the vapors must be removed to prevent oil contamination that leads to sludge formation. The positive crankcase ventilation (PCV) system siphons these vapors from the crankcase and routes them into the intake manifold so they can be reburned in the engine.
The main component in the PCV system is the PCV valve, which is usually located in the valve cover. A hose connects the PCV valve to the intake manifold. The PCV valve is a spring-loaded valve with a specific orifice size designed to restrict the amount of air that's siphoned from the crankcase into the intake manifold. This is necessary because air drawn through the valve from the crankcase has a leaning effect on the fuel mixture much the same as a vacuum leak. So air flow through the valve must be controlled within certain limits. At idle, air flow is reduced because little blowby is produced. When the engine is cruising and vacuum is high airflow through the PCV valve is at a maximum to purge the blowby vapors from the crankcase.
Sounds great, but it's stupid. It causes carbon deposits on the valves, and just is not efficient, along with many, many recorded failures by nearly everyone.
Possible symptoms caused by a faulty PCV include but are not limited to:
-Slight drop in boost pressure, ie. a ~2 psi drop across the board.
-Some oil will be pushed out through the oil filler cap, and onto the valve cover, and may possibly go towards the coil packs. There may also be some oil on the bottom side of the engine cover, where the oil filler cap is be some oil on the bottom side of the engine cover, where the oil filler cap is.
-There might be a slight decrease in MPG.
-Sometimes, strange noises like whistling from that area.
Easiest way to check if yours is bad is to remove this:
Once that is removed, try blowing into the flexible pipe. You should not be able to blow through this. If you can, you have to make a choice of three options.
1. Replace with OEM part # 06F129101P for roughly $75, risking the same thing happening again in the future.
2. Cheap and easy "PCV Fix" of which I will discuss the downside.
3. Look at your catch can options.
The PCV Fix
The PCV Fix is a quick, easy, cheaper way of fixing your broken PCV. Sounds great, right? Nope. This should only be temporary. Reason being, it is sealing the issues caused by a broken PCV, but also allowing everything that should be filtered out back into the engine to turn into sludge. Sure, use this as a cheap fix while you save for a catch can, but don't keep it forever.
The Catch Can
Catch cans consist of metal construction that won't break with age. They catch harmful moisture and groooooss oil deposits instead of returning it into the engine to be burnt into carbon deposits. It also seals any places left for our precious boost to escape.
There are two main types of Catch Cans. The closed-system, and the vent-to-air system. Both have their benefits, but only one is street legal.
Vent-to-air systems do just that. Vent all the nasties straight into the air. Mostly used in racing applications. It is bad for the environment, and can really make a mess. This is probably the best system for your car, but not really the one you should go with.
The closed-system instead of letting all the grossness out, uses a series of screens/baffles/filters to force oil and moisture to the bottom of the catch can where you can empty it out into a cleaner/safer depository. This is the most likely system for our cars.
There are many, many options for a catch can setup for our cars. You can even do custom setups from many ebay type options. There are also many full kits comprised of everything you need, which are the options I will lay out before you, in no specific order.
BSH is probably one of the more widely known companies for catch cans for our system. They have products ranging from just a block off plate that you can use with any catch can system, to stage 2 and even a racing staged version. Stage 2 is the most viable solution at this point.
PROS: IMO, best complete system for the lowest price
Most common/popular brand/model
Boost tap can be added to the block off plate for an extra boost source
Good quality, good reviews
All necessary hardware
CONS: Brass fittings look out of place
Not as good looking as other options
No way to tell how full it is without removing it
No interior baffles or screens to aid in gunk collection
You say you want something a little fancy looking? Look no further than Eurojet's option.
A little pricier than most at ~$300, but you gotta pay for flamboyance.
PROS: Look how fancy it is!
Combines catch can technology AND vent-to-air in one system (confirm?)
Has a gunk level window for removal-free checking
Very high quality components
Larger than average tank capacity
Has a quick drain valve for non-removal emptying (confirm?)
CONS:Too fancy?
Pricier than other systems
Vents to air
Just judging from the picture, the block off plate doesn't look right, so you may need to source a different one? (confirm?)
Priciest one of the bunch @ ~$400, but definately the most OEM looking of any I have seen.
PROS: Damn that looks OEM!
Very high quality
Looks like it has a quick drain plug as well (confirm?)
CONS:Holy shit it's expensive
As far as I can tell, no way to check gunk level without removing (confirm?)
On to my personal favorite, and a fairly new product from the guys over at 034.
At ~$285, I feel this is the best bang for your buck as far as quality, look, performance.
PROS: IMO the most complete system available
Vortex (think Dyson) design to force oil to the bottom
Has an oil return line that can filter out oil and return it to the oil pan
comes standard with a boost tap on the block off plate
Very high quality for it's cost
Custom molded silicon hoses
CONS:Must be removed to check level
Engine cover must be cut to fit back on
Um, that's it? (confirm?)
There are numerous other options including AMW, 42DD, etc...that make great catch cans, but they leave you up to your own devices when connecting it properly to your engine. I also leave it up to you to find for yourself which is best for your needs. Keep in mind, certain catch can kits made for other various 2.0tfsi applications will also work, ie. Jetta, Golf, etc.
MAINTENANCE: Yes, you don't get off scot free on this one, but no worry, it is easy. They need to be drained from time to time. This may be easier on some models than others. Gunk will collect in there. Oil, water, etc. you will want to check it often at first. Once you see for yourself how much stuff accumulates, you can deem how often it's necessary. Also, if you live somewhere with winters, you will want to check it more often in freezing temperatures. Ice can form inside, harming components, blocking pathways, etc.
Feel free to add input or correct me on anything. Bear in mind, I created this entire thread on my phone over the last few hours. Yes, literally hours, so hopefully all links and pictures work properly, as I cannot tell until I submit. I will fix and update this evening as needed.
Very well done Jim. I've read other threads and had a good idea of the benefits of a catch can, but this goes into more detail for us noobs. I don't know about everyone else, but I vote for a sticky!!!
-Joel
2005.5 Audi A4 Brilliant Black on Black: RAI Testpipe/Downpipe, Audiup Race Red Snub Mount, K&N Drop-In, NGK BKR6EIX Plugs, Emilgevor Interior LED Kit, S-Line Rear Valence, 20% Tint, Custom Painted Center Caps, OEM Bi-Xenon Blacked Out with Phil's Clear Corner Caps, Rev. D Diverter Valve, 19" VMR V708's Gunmetal wrapped in 225/35/19 General Exclaim UHP, Black Plasti-dipped Window Trim, PODI Mechanical Boost Gauge
Could provide links for DIYs of other people's catch can installs.
Can also describe the differences in the kits. Aren't some just catch cans while others (like 034) also recirculate the oil and just catch the other stuff?
Disclaimer: In no way shape or form is the comment above representative of a car expert. It is merely the understanding and/or opinion of a car enthusiast, and as such, the knowledge he/she possesses may or may not actually be the truth.
Does a catch can setup eliminate the need for bsh pcv fix?
Short answer, yes. It would replace it altogether. The pcv fix just eliminates the pcv, but instead of catching the junk, it lets all of it back into the engine. It fixes a broken pcv, but doesn't fix problems of gunk and moisture.
To other suggestions: slowly working on them as we speak. This shall be the most epic cell phone thread of all time!
Cool writeup.
Do you need to drain or empty the catch can periodically? Just do this with your regular oil change?
Yes. It will fill with nasties that should be emptied. Some cans come with dipsticks/windows to see how full it is. Others you just have to guess. Winters they will fill up with more moisture, so you must check it often so it doesn't freeze and cause problems.
sticky material imo, great reference but i would also add there are types of catch can systems
closed, (bsh, 034, etc)
and vent-to-atmosphere or Race set ups (bsh also has this option, and the easiest to identify is the eurojet one)
im not sure what the gains/losses are with either set up i just know that vent to atmosphere when the filter gets dirty it can start to mess up your engine bay with oily vapors
Scott
I don't even have an audi....i just love me some 'zine
America is all about speed, hot, nasty, bad-ass speed - Eleanor Roosevelt
Short answer, yes. It would replace it altogether. The pcv fix just eliminates the pcv, but instead of catching the junk, it lets all of it back into the engine. It fixes a broken pcv, but doesn't fix problems of gunk and moisture.
To other suggestions: slowly working on them as we speak. This shall be the most epic cell phone thread of all time!
thanks, great write up btw.
so i guess its a good thing i didnt buy both the pcv fix and the catch can kit
034 catch can kit it is!
I went with the 034 catch can set up and have no input at all as it's still sitting in a box in my garage waiting for its time to shine. Looks to be good build quality though.
So I am on the verge of getting the 034 can (going back and forth with the 42dd and 034, but the molded hoses are putting it in the lead) but I have a few questions that I have not seen answered to my satisfaction yet.
Has anyone with the 034 can taken a look inside? is it simply an empty can that relies on the "vortex" entrance of the tangentially directed in-port for vapors to condense on the walls of the can or is there a series of mesh screens as well like the 42dd has that allows condensation to adhere to?
Has anyone tested what comes out of the 034 can to make sure it isn't a bunch of crud that is being returned to the oil pan. Based on everything I have read, and despite Laslo as some point exclaiming that it is perfectly clean, I have my doubts. I thought the whole idea of a catch can is to catch the crap so it doesn't get recirculated...
Has anyone "lightly trimmed" their engine covers to fit yet, would lke to see how much "light" trimming is involved. I wanna keep as OEM looking as possible.
This is a great write up, thanks Jim for taking the time. Sticky!
08 A4 2.0T Quattro 6MT S-Line QGM
APR Stage 1 | Stasis Catback Exhaust | 034 HFC | K&N Drop-in Filter | 034 Turbo Inlet Hose | Rev. D DV | AudiUP Red Race Mount | VEI Boost Gauge | Custom HID Fogs (Blazer retrofit) 3000K
I kind of wondered that as well, but didn't want to clog the original post with opinions and hear say. It would be nice to see the inside of each one. I also wondered how the oil is safe to return to the oil pan, if it's mixed with crap. But you can always close that circuit and use it as a normal catch can.
If there is ice inside, you can't/shouldn't start the car? This might happen if you park outside overnight in the Canadian winters, or are we talking about a longer time frame?
the reason why you want to watch your fluid levels in the winter time is bc if it gets above the hose levels, and then freezes then you have an issue on your hand, however, if you monitor the levels and keep them below the hoses, you're golden
and if its really really full, and it freezes(overnight) you may break the can
Scott
I don't even have an audi....i just love me some 'zine
America is all about speed, hot, nasty, bad-ass speed - Eleanor Roosevelt
That really sucks that there are no baffles/filters/screens to collect oil. You just gotta hope it has enough time in the can to condense on the walls, I guess. -1 point for the bsh. Will add to cons.
Just found out the 034 requires cutting of the engine cover in order to make it still fit.
Phil, did you solve this?
Want to add it to the cons, but I think I have reached my character limit for one post. Or else my phone just isn't working right. Can the mods extend this for me?
You say these catch cans wont put the gunk back into the intake manifold any more. So does this mean you wont have the build up on the intake valves? Hence, removing the cost to get the valves cleaned every 100k miles (or what ever they need it...still very n00b) (dont even have an Audi yet but doing lots of research to be prepared to get one) :)
Personally I think the Provent catch cans are the best option. They have replaceable filters that are easy to get to and a return drain option. I'm planning on getting one and using it with my stock PCV and some high temp clear tubing to see what beeing moved around.
You say these catch cans wont put the gunk back into the intake manifold any more. So does this mean you wont have the build up on the intake valves? Hence, removing the cost to get the valves cleaned every 100k miles (or what ever they need it...still very n00b) (dont even have an Audi yet but doing lots of research to be prepared to get one) :)
As far as I know, you will always have small build up over time. You do a catch can, and meth injection, and that is the best preventative maintenance you can do for it.
Yes this should help with carbon buildup, combine catch can and meth and I don't see carbon buildup ever being a problem.
I can vouch for the 42DD, has internal baffles, great looking can available in numerous finishes. Competitive price. Only drawback was having to retrofit it for the B7A4 bay because it's made for the mkiv Gti
Unfortunately carbon build up is a fact of the FSI engine, cc or no cc. This is covered extensively on other threads and in the RS4 forum more thoroughly. I can't remember if it was on AZ or another forum, but the OP did an N=1 study where he showed his valves at ~50k miles with the carbon buildup, did an open cleaning, installed a CC and then followed up with a ~30k-40K later picture of the valves. Minimal decrease in carbon build up, but helped some nonetheless, but in no way a solution for the eventual problem. IMHO is that the cc is a reliable solution to the problematic PCV as noted above by Jim. Other minor benefits might be to decrease some of the carbon buildup, but using a fuel additive, or W/M and making sure to use quality fuel in the first place is the best defense against carbon build up. Sorry for getting a little off topic, but it all relates IMO.
08 A4 2.0T Quattro 6MT S-Line QGM
APR Stage 1 | Stasis Catback Exhaust | 034 HFC | K&N Drop-in Filter | 034 Turbo Inlet Hose | Rev. D DV | AudiUP Red Race Mount | VEI Boost Gauge | Custom HID Fogs (Blazer retrofit) 3000K
Seanb7 , does that solution replace the pcv or work in tandem with it.
I'm sure you can run it both ways. It looks like most of the catch can solutions available for our cars have 1 inlet and 1 outlet port with a drain port at the bottom.
If there is ice inside, you can't/shouldn't start the car? This might happen if you park outside overnight in the Canadian winters, or are we talking about a longer time frame?
This is freaking me out now and I'm thinking I might just block the return line from my 034 CC from the can that recirculates the oil back into the turbo return line...
REVO Stage 2+ | REVO SPS Switch | APR Carbonio | R.A.I. HFC and DP | Custom Milltek Quad Tip Exhaust | 034 Oil Catch Can | 034 Turbo Inlet Pipe | Forge DV and Spacer | APR Snub Mount | Autotech HPFP | HPFP PRV | Votexx RS4 wing | Cupra R Lip | RS4 Fog Grilles | RS4 Stealth Bulbs | OEM Bi-Xenon headlights | B5 Lowering Caps | LED License Plate Bulbs | Gominigo Plate kit | VAST Meth kit | RS4 Rear Sway Bar | PODI Dual Steering Column gauges | Painted Reflectors
Seanb7 , does that solution replace the pcv or work in tandem with it.
I'm sure you can run it both ways. It looks like most of the catch can solutions available for our cars have 1 inlet and 1 outlet port with a drain port at the bottom.
Got my 034 oil catch can installed and did enough trimming to get the cover back on
The back "pin" on the cover does not go in, but that would take even more trimming which I didn't want to do... the way it is right now, the cover is secure and will not come off. It's definitely NOT what I would call "Minor" trimming
REVO Stage 2+ | REVO SPS Switch | APR Carbonio | R.A.I. HFC and DP | Custom Milltek Quad Tip Exhaust | 034 Oil Catch Can | 034 Turbo Inlet Pipe | Forge DV and Spacer | APR Snub Mount | Autotech HPFP | HPFP PRV | Votexx RS4 wing | Cupra R Lip | RS4 Fog Grilles | RS4 Stealth Bulbs | OEM Bi-Xenon headlights | B5 Lowering Caps | LED License Plate Bulbs | Gominigo Plate kit | VAST Meth kit | RS4 Rear Sway Bar | PODI Dual Steering Column gauges | Painted Reflectors
Personally I think the Provent catch cans are the best option. They have replaceable filters that are easy to get to and a return drain option. I'm planning on getting one and using it with my stock PCV and some high temp clear tubing to see what beeing moved around.
Just placed my order for the 034 model. As many can tell, I don't have a show quality engine bay, so the engine cover doesn't matter to me. Wish I had the extra hundo for the BFI clean catch system, but I am totally happy with my decision. Thanks to the OP for this informative thread! Hopefully now all the tommy knockers will be eliminated from my car.
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Originally Posted by fordyoz
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