B7 A4's 2.0T DEFECTIVE valve cover

[markcm]

EDITED: While I thought replacing the valve cover and PCV combo with a working set stopped the oil from collecting in the intercooler, it did not. I ended up pulling the turbo to find the waste (penny) valve was really loose, the turbo housing had cracks, and the nut holding on the impeller was eroded horribly.

I bought a new turbo and after 1k miles there is almost no oil in the intercooler. It has consumed some oil but its still within Audi's "1Qt/1k mile" is ok tolerance.

ORIGINAL POST:

I will add my recent experience for anyone else currently experiencing oil collecting in their intake and passing through the engine causing oil smoke

Our new to us 2007 A4 Avant with 2.0t was loosing oil at about 1qt per 500 miles. I eventually found that the intercooler cross pipe was filled with oil. After researching I tried replacing the PCV valve with a new OEM unit which made no difference and inspecting the OEM one I took off, aside from being full of oil it looked rather new. Digging through records I got from the previous owner their mechanic had recently replaced this, it seems they were offloading their problems without telling us as I specifically asked about oil consumption when we bought it and they said "uh, no, nothing unusual".

Next, I bought a chinese no-name valve cover for $120, part number REPA320401. Installing this increased the issue significantly. We'd blow a half quart every time we drove the car along with batman-grade smoke screens at cold start and on hill climbs. The PCV also would not fit flush and the 1/4" nipple next to it was too small on the I.D. for the hose that connects to it.

Luckily I also have a 2005.5 A4 B7 avant with 2.0T so I swapped this chinese valve cover and new OEM PCV valve as this car doesn't consume any oil. The first drive it blew a quart in 60 miles and then smoke screened the parking lot on the first following cold start. The oil issue followed the valve cover/PCV assembly.

So, our original 2007 valve cover had failed somehow although there were no visible indications it was failed. The PCV valve on both cars were fine. For the record, the failed OEM valve cover was black, the one that was working was from my 2005.5 2.0T A4 avant was silver. I bought another used silver one from ebay and it works great; neither car are loosing oil or smoking now.

[funkypterodacty]

Great info markcm, I too have heard that the silver valve covers aren't as prone to failure like the black ones are.

[klrider44]

Great info markcm, I too have heard that the silver valve covers aren't as prone to failure like the black ones are.

For what's it worth I originally had a silver valve cover and it failed. I picked up a low mileage black one and have been good since then. The black one it is the updated part number. Basically they both suck lol.


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[Brillo]

Interesting. It's easy enough to test the VCs, especially when off the engine. Just pressurize the passage through the VC (front PCV port on the left side and larger front port on the front right side) and either spray soapy water on the underside plastic welds or dunk the whole thing in a tub of water. The welds are virtually always the point of failure. You should see lots of bubbles at the failure point.

[Charles.waite]

The silver ones are from BPG engines and the black are from BWT.

they have slightly different PCV functionality (hence you see a vin split on PCV parts on ECS and Europa, etc). One isn’t better than the other, they’re just different. You can swap them however you want but you should use early vin PCV parts with a silver VC and late vin PCV parts with a black VC.

[Bjoern]

Had similar problem with massive oil leak into turbo PCV with a gallon of oil in IC system and whistling sound heard from engine under boost. Removed valve cover and found leak into exhaust port to turbo as described above.
Pried underside of cover off (see post on YouTube) and cleaned everything thoroughly before reassembling using J-B Weld Plastic Weld Gel Epoxy along all seams. Also looked and fixed leaks along evap channel. Epoxy based cement should be tolerant to temperature encountered.

Car runs well after fix and whistle is gone.

I think I have found the reason for the symptoms: The combination of normal flow induced pressure drop across the restriction imposed by the PCV valve and a cracked cover will lead to a net pressure differential between the air entering the camshaft housing through the large secondary oil separator port and the exit to intake pipe. Air will thus bypass the PCV and reenter the exhaust port to turbo at the lowest point along the edge of the valve cover where oil will gather. Any oil there will be sucked into the intake.

[funkypterodacty]

Hmm I may do what you did prior to installing my brand new valve cover, I have concerns tho if some of the epoxy/j-b weld comes loose, what could that cause ?

[Brillo]

I think I have found the reason for the symptoms: The combination of normal flow induced pressure drop across the restriction imposed by the PCV valve and a cracked cover will lead to a net pressure differential between the air entering the camshaft housing through the large secondary oil separator port and the exit to intake pipe. Air will thus bypass the PCV and reenter the exhaust port to turbo at the lowest point along the edge of the valve cover where oil will gather. Any oil there will be sucked into the intake.

I'm unsure about what you are describing. This is typically what happens when the pre-TC passage in the VC is cracked: The secondary oil separator is completely open to the crankcase (as is the whole cam area under the VC) so there is no pressure differential between these areas. Only under boost conditions is there any draw of crankcase blow-by gasses (no air involved) into the pre-turbo port and on into the cold section of the TC. Under these conditions the PCV valve is not activated although the blow-by gasses do travel through the PCV valve from the secondary oil separator into the VC passage to the pre-turbo port. There is not much flow, just enough to prevent positive pressure in the crankcase. The oil doesn't enter this system until after the PCV valve. Under boost, some of the oil splashing around under the valve cover can get sucked into the pre-TC passage in the VC (only) if it is cracked, and then flows downhill into the TC and collect in the IC piping. Some if it eventually might get pushed into the IM and burned during combustion. Does this comport with what you are saying?

[Bjoern]

I’m describing the situation under boost with positive pressure in intake manifold and low pressure in pre turbo intake. A communication between the crankcase and pre TC passage at the level of the exit port will force oil into the TC passage since it is at a point where oil will gather ( the engine is tilted to that side)
No smoke and no oil leak since repair.
J-B weld epoxy can tolerate 500F per their website- hotter than what you will encounter in the valve cover. It is resistant to oil and gasoline.

[i3oricua]

So I find this extremely interesting. So interesting that I went and bought some epoxy (super steel because....England) and took my valve cover off. I haven’t started filling in cracks yet but mainly because I don’t want to go overboard. So if you’ve filled in the cracks which ones did you go with? I’ve posted up pics of the concerning areas on my valve cover. They’re not actually cracks but areas where the seam seems to have come apart a little bit.




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[80sGuy]

^^I know the original OEM part might cost a pretty penny but isn't it best to replace a new Valve Cover instead of possibly opening a can of worms for the future to come???

[i3oricua]

^^I know the original OEM part might cost a pretty penny but isn't it best to replace a new Valve Cover instead of possibly opening a can of worms for the future to come???

While that is logical the problem is still likely to come back. I still don’t know what’s causing the issue. This is my second valve cover and if the issue persists then I will likely go down that route but for now doing this “should” not hurt anything and hopefully provide some improvement.


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[i3oricua]

So here’s a little progress pic. Have to wait for the epoxy to cure and then I’ll slap it on. 🤞🏾



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[Brillo]

Looks like you've got it covered. On your last photo it is the weld seems for the passage from the large port (upper left in your photo) diagonally downwards to the forward most PCV port which is not seen in your photos. Never tried that stuff in a hot oily application. Hope it works. Brillo

[Brillo]

I’m describing the situation under boost with positive pressure in intake manifold and low pressure in pre turbo intake. A communication between the crankcase and pre TC passage at the level of the exit port will force oil into the TC passage since it is at a point where oil will gather ( the engine is tilted to that side)
No smoke and no oil leak since repair.
J-B weld epoxy can tolerate 500F per their website- hotter than what you will encounter in the valve cover. It is resistant to oil and gasoline.

Under boost conditions there is no communication between the pressurized IM and the crankcase via the PCV valve provided it is functioning properly. There is a check valve to prohibit flow up the hose to the PCV valve and on into the crankcase. I believe also that the valve itself in the default position blocks flow from the iM. It's only when the vacuum in the IM sucks the diaphragm down that the communication is present between the crankcase and the IM, and the vacuum in the IM serves to scavange the crankcase blow-by gasses into the IM under non-boost conditions.

You are absolutely correct that when under boost oil that has seeped through cracks into the VC passage will get sucked/pushed towards the pre-TC port and on into the TC due to the pressure differential.

[Bjoern]

I removed the plastic part at the bulkhead end completely to clean the edges thoroughly. https://youtu.be/2HRNbY5TPIk

I then applied a bead of epoxy along the edge and at the exit of the vent to the TC. The image will give you an idea of where to apply the epoxy. I made sure not to apply any resin to the inner lip op the valve cover in order not to interfere with the CC gasket.


https://www.dropbox.com/s/d1f92immrr..._2683.jpg?dl=0

[Bjoern]

I meant to say that the blow by from crankcase will still pass through a rather narrow and convoluted passage involving the secondary oil separator and then behind the closed PCV valve and back into the pre TC channel in the VC. If a leak exis the pressure differential between the entry point of crankcase gasses and the exit port to the TC will be significant

[Brillo]

Absolutely true, and that's how so much oil can get sucked down the pre-TC port.

[Bjoern]

Update after about 1K miles: essentially no oil consumption and no oil in intercooler.

[Brillo]

Update after about 1K miles: essentially no oil consumption and no oil in intercooler.

Great! Good news.

[markcm]

I will add my recent experience for anyone else currently experiencing oil collecting in their intake and passing through the engine causing oil smoke

Our new to us 2007 A4 Avant with 2.0t was loosing oil at about 1qt per 500 miles. I eventually found that the intercooler cross pipe was filled with oil. After researching I tried replacing the PCV valve with a new OEM unit which made no difference and inspecting the OEM one I took off, aside from being full of oil it looked rather new. Digging through records I got from the previous owner their mechanic had recently replaced this, it seems they were offloading their problems without telling us as I specifically asked about oil consumption when we bought it and they said "uh, no, nothing unusual".

Next, I bought a chinese no-name valve cover for $120, part number REPA320401. Installing this increased the issue significantly. We'd blow a half quart every time we drove the car along with batman-grade smoke screens at cold start and on hill climbs. The PCV also would not fit flush and the 1/4" nipple next to it was too small on the I.D. for the hose that connects to it.

Luckily I also have a 2005.5 A4 B7 avant with 2.0T so I swapped this chinese valve cover and new OEM PCV valve as this car doesn't consume any oil. The first drive it blew a quart in 60 miles and then smoke screened the parking lot on the first following cold start. The oil issue followed the valve cover/PCV assembly.

So, our original 2007 valve cover had failed somehow although there were no visible indications it was failed. The PCV valve on both cars were fine. For the record, the failed OEM valve cover was black, the one that was working was from my 2005.5 2.0T A4 avant was silver. I bought another used silver one from ebay and it works great; neither car are loosing oil or smoking now.

Folks, I am back to report while I thought replacing the valve cover and PCV combo with a working set stopped the oil from collecting in the intercooler, it did not. I ended up pulling the turbo to find the waste (penny) valve was really loose, the turbo housing had cracks, and the nut holding on the impeller was eroded horribly.

I bought a new BW turbo and after 1k miles there is almost no oil in the intercooler. The car is more responsive and while it has consumed some oil but its still within Audi's "1Qt/1k mile" is ok tolerance.

[A4_Alboy]

Hi everyone.

Sorry to jump in here, but I came across this thread while researching a fault with my A4 B7 2.0tfsi with BWE engine, which I suspect could be a faulty passageway in my V.C.

To start with I noticed a slight whistle from the engine on light throttle when cold. Then I noticed it idles rough when dipstick or oil filler cap are removed and it appears to be sucking air into the engine when the cap or dipstick are removed. Initially I thought it was a faulty pcv valve but after replacing it today it is still doing the same. Also seems to be down slightly on mid range power. Engine idles fine and runs well otherwise and haven't noticed an excessive oil consumption issue, that said I do only use the car on weekends.

Could the V.C passageway fault/cracks that everyone is talking about here cause this?

I'm suspecting it's drawing from a split in the passageway that connects the front pcv to the rear pcv and I'm thinking of blanking the pipe that goes to the turbo compressor housing as diagnostic test but don't know if it's a good idea or not.

Thanks in advance for advice or info given ;-)

[Brillo]

To start with I noticed a slight whistle from the engine on light throttle when cold. Then I noticed it idles rough when dipstick or oil filler cap are removed and it appears to be sucking air into the engine when the cap or dipstick are removed. Initially I thought it was a faulty pcv valve but after replacing it today it is still doing the same. Also seems to be down slightly on mid range power. Engine idles fine and runs well otherwise and haven't noticed an excessive oil consumption issue, that said I do only use the car on weekends.

Could the V.C passageway fault/cracks that everyone is talking about here cause this?

I'm suspecting it's drawing from a split in the passageway that connects the front pcv to the rear pcv and I'm thinking of blanking the pipe that goes to the turbo compressor housing as diagnostic test but don't know if it's a good idea or not.

Rough idle is completely normal when the dipstick or oil fill cap is removed. At idle the PCV valve is allowing the IM to draw a partial vacuum on the crankcase to scavenge blow-by gas. When you remove the dipstick or oil fill cap you are creating a major unmetered air leak into the induction system, so it runs rough. There are numberous sources for the whistling noise, two of which are a defective diaphragm in the main PCV valve (which you replaced) or occasionally one of the two check valves in the PCV system. There are two versions of the PCV valve depending upon the age of your engine. The older version has both check valves in the PCV valve assembly and the newer has one just before the line that runs to the IM. The other was moved to the top of the right side front breather that goes to the pre-TC port. If you have the newer version check the one in the breather to make sure it's not leaking and causing a whistling noise.

shiro1745 has created an excellent series of photos and explanations of the PCV system on page one at this link:

https://www.audizine.com/forum/showt...stem-explained

Charles shows photos of the old and newer version of the PCV valve at post #15 of this same thread.

You state that you are not consuming oil which would indicate that the 1-f / 1-r passage way through the VC is intact. If you want to test it without removing it to be certain follow the instructions in this link (below) at post #39:

https://www.audizine.com/forum/showt...-PCV-Valve-Fix

[a1dan_87]

I'll share my experience here. Yet to replace the valve cover, as I'm not the owner of the A4 in question. I daily carpool with my brother, who's car I work on. Constantly. After a new PCV valve the car started drinking a quart or more every 200 ish miles or less. It was ignored despite my advice on figuring out what it was. A week or so later, after constantly filling the oil, the car went up in smoke pulling onto the highway. The turbo had blown (later found to have practically drowned in oil from VC) and we garaged it. About a month ago we got the new turbo in, and the issue is only slightly better- let's say a quart every 350 miles. I know it's the VC, as there's oil in the intake and the breather hose from the VC into the Intake. Intercoolers and piping on the passenger side turbo outlet had a pint or two of oil in them. Seems like an extreme case on my part, the oil light coming on every 250-350 miles now.

The car continues to be driven, the issue ignored by the driver (brother) and title holder (step father).

Guess we'll see how it plays out, but this is an extreme case of PCV and VC issues. Ours seemingly drowned the turbo or caused issues with it.

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[80sGuy]

I'll share my experience here. Yet to replace the valve cover, as I'm not the owner of the A4 in question. I daily carpool with my brother, who's car I work on. Constantly. After a new PCV valve the car started drinking a quart or more every 200 ish miles or less. It was ignored despite my advice on figuring out what it was. A week or so later, after constantly filling the oil, the car went up in smoke pulling onto the highway. The turbo had blown (later found to have practically drowned in oil from VC) and we garaged it. About a month ago we got the new turbo in, and the issue is only slightly better- let's say a quart every 350 miles. I know it's the VC, as there's oil in the intake and the breather hose from the VC into the Intake. Intercoolers and piping on the passenger side turbo outlet had a pint or two of oil in them. Seems like an extreme case on my part, the oil light coming on every 250-350 miles now.

The car continues to be driven, the issue ignored by the driver (brother) and title holder (step father).

Guess we'll see how it plays out, but this is an extreme case of PCV and VC issues. Ours seemingly drowned the turbo or caused issues with it.

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Did you replace the corresponding ‘turbo inlet valve’ (metal tube feeding to the turbo) with the new pcv? Both would need to be updated at the same time.

[a1dan_87]

Did you replace the corresponding ‘turbo inlet valve’ (metal tube feeding to the turbo) with the new pcv? Both would need to be updated at the same time.

Nope, and that was the mistake. I think it lead to a crack in the valve cover, and was sucking oil in ridiculous amounts.

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[klrider44]

Nope, and that was the mistake. I think it lead to a crack in the valve cover, and was sucking oil in ridiculous amounts.

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These valve covers seriously blow, I would be willing to bet that most people that have oil consumption issues have a cracked valve cover.


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[B7TitaniumA4]

Bump to add content

[B7TitaniumA4]

Sorry, wanted to do this through Tapatalk for ease of picture Sharing.

This info is in regards to the GTI VC talked about earlier.

My factory part number from my 2008 BWT:
06D 103 469 M
40 10180D

The GTI cover I bought for $70 cheaper than the A4 ( on ECS) came with VC gasket, PCV gasket and new mounting bolts.
06F 103 469 K
40 10180 H

As mention before the GTI cover comes with a raised oil fill neck due to their engine covers containing part of the intake system. This neck can be removed with some heat and force, and then our oil caps fit fine after a little cleanup of the area. The quality looks great on this too. (Genuine Audi/VW)

I hope this helps in decision making and saving some money.










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[Krmass25]

Had to do the valve cover after what looked like a catastrophic failure oil cloud and engine lights and went for the CTS billet piece. The engine has never performed better. it tightens everything up a great deal. Forget that plastic piece of crap! You just have to adapt some 8AN hoses and fittings to re-route the PCV system and you re good to go. If anyone needs help just ask.

Don't get the plastic one ever if you have the option

it is a sucky leaky piece of crap.

[B7TitaniumA4]

Nice opinion on the subject, but not everybody has the budget to get a billet cover. The plastic ones just seem to have a “ life span” once that lifespan ends, buy a brand new one of good quality and ride it out until it does again. Seems like most are going well into the first 100k miles and then start to come apart. I’m updating my entire PCV system at the same time as well.

[Charles.waite]

Yea the issue with the billet ones is you can’t retain the factory PCV system. Which to me isn’t a positive.

[newa42me]

Best place to buy an aftermarket VC?

[Krmass25]

THE BILLET COVER IS ONLY $300 NOW

https://www.ctsturbo.com/product/cts...over-2-0t-fsi/ $300
That is the real deal. When you add up the cost of time and hassle, gaskets, labor etc it completely negates not buying the metal one. Replacing the plastic junk once is a waste of time. buy solid metal. that is what engines are made of.

Then order
- 10mm to 8AN bung fitting with 90degree bend to screw into valve cover.
- 10ft or so 8AN braided hose from summit
- summit swivel type quick connectors. 1 x T / 2 x straight connectors
- catch can. I recommend one that uses 8 AN fittings to match your setup. 034 has one that works. It came with 90 degree fittings that matched the fittings I bought and the whole setup came together without any issues.

use a T at the valve cover to go one side to the oil separator and the valve cover port on the other side and the third center line goes to the left side of the catch can. Right side of catch can connects across to turbo vent tube(longest hose routes above radiator tucked down where you don't see it.

There is a small hose that you route around the valve cover using a simple black rubber tube. cut off the length you need from auto store and just hose clamp to existing line. Super easy and far superior to factory.

I can take pics of my setup if you are interested. Never leaked a bit and car is much tighter. Way less oil loss.

[mgfranz]

Best place to buy an aftermarket VC?

"Best place"? There are dozens of places, I found this one, on eBay. While i'm sure it's not OEM, it is aftermarket. Real OEM will cost you over $300 in most cases.

[esandes]

Is there a DIY thread to replace the VC?

[mgfranz]

Is there a DIY thread to replace the VC?

Why would you need one? 30 min. job at best. Remove the PCV, remove the bolts, remove the coils, replace. Reverse the procedure..

[Adams-Allroad]

My and friends 2006 a6 valve cover leaked oil filler.
May issues with valve cover


I have pictures.

My 2013 has aluminium valve cover, thank god.

[Ray1031]

Is there a DIY thread to replace the VC?

Here's one,

https://www.audizine.com/forum/showt...ver-Gasket-DIY



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[esandes]

Here's one,

https://www.audizine.com/forum/showt...ver-Gasket-DIY



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Lol that bolt sequence....i knew it was going to be hairy.