T2B5 TDI Exhaust Valve maintenance

n1das

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Here's a maintenance heads up on the exhaust valve in our CR TDI's uber-expensive exhaust system.

I was at mrchill's shop yesterday getting a metal skidplate installed on my 2010 JSW TDI. I got to get under the car and take a good look at everything including the exhaust system. Chris pointed out that he recommends lubing the exhaust valve mechanism with a penetrating lubricant once in a while. A few '09 and '10 CR TDI owners have had this valve replaced under warranty after they have developed problems. We suspect the problems could have been prevented by periodically lubing the mechanism. The valve assembly may pick up dirt and road salt and who knows what other crap on the outside and cause the mechanism to get sticky.

Chris (TDIclub mrchill) gave the exhaust valve spring a squirt of penetrating lubricant and I've noticed the valve is now quieter. You can hear this valve move at shutdown. When you shut the engine down, the shutdown is followed by a "chunk chunk" sound heard from underneath the car. Mine was quiet when the car was brand new and became louder after a while. It is now much quieter since being lubed with a penetrating lubricant.

Here's the exhaust valve in my JSW TDI: (cell phone pic)


Location in T2B5 exhaust system:


The exhaust valve is highlighted in the T2B5 pic.

A good time to do this maintenance is during an oil change when you have the car up on ramps to drain the oil. Crawl a little further underneath and give the spring a squirt or two with a good penetrating lube. I do all my oil changes topside with an extractor pump so now I'll have to put my JSW TDI up on ramps once in a while.
 
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eb2143

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Is that some type of spring exposed there in that first picture? I guess on the upside they made it easy to lube & apply protectant to, but that sure looks like an obvious problem/oversight considering our weather and the length of time we expect these cars to last.
 

n1das

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Is that some type of spring exposed there in that first picture? I guess on the upside they made it easy to lube & apply protectant to, but that sure looks like an obvious problem/oversight considering our weather and the length of time we expect these cars to last.
The spring is exposed and hence our concern. :eek: Anytime an 09 or newer CR TDI comes in his shop he now routinely gives the spring assembly a squirt or two of penetrating lube.
 
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n1das

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I don't think the noise it makes correlates with anything but our concern is it may eventually become sticky if not lubed once in a while. At least we know it's working when we hear the noise at shutdown.
 

740GLE

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The one area off issue I heard with these vavles was internal cleaning was needed. Lubbing up the outside certainally isn't a bad idea, and I'll def be doing this from now on, but it may not prevent the internal clogging. So drive em hard and clean out the crap.
 

aaronazevedo

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2010 Jetta Cup
What is the function of this valve? Is it something that can be removed and therefore the system simplified?
 

n1das

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What is the function of this valve? Is it something that can be removed and therefore the system simplified?
IIRC, the purpose of the valve is to restrict the exhaust slightly to help raise EGTs during DPF regen operations to maintain the DPF. EDIT: It may be related to EGR function. I don't honestly don't know.

Removing it will likely trigger a CEL. I suggest the valve not be removed unless you're willing to spend $2k for a new DPF a few thousand miles later. It's not hard to lube it once in a while.

LOL, may we could figure out how to operate it as an engine brake, aka Jake Brake. :)
 
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n1das

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The one area off issue I heard with these vavles was internal cleaning was needed. Lubbing up the outside certainally isn't a bad idea, and I'll def be doing this from now on, but it may not prevent the internal clogging. So drive em hard and clean out the crap.
Agreed. That's exactly what I do with mine. The majority of my driving is spent aggressively haulin' arse on the highway for up to an hour or more at a time. :cool: I make relatively few short trips and I do not baby the car. The owner's manual specifically recommends avoiding short trips of less than 15 minutes duration to ensure complete warmup and allow a scheduled regen operation to complete itself.

"Drive it like you stole it" describes it best. :cool:
 

740GLE

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I thought the flapper was for more effective use of the high pressure EGR system, where the low pressure EGR it's not needed.
 

n1das

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I thought the flapper was for more effective use of the high pressure EGR system, where the low pressure EGR it's not needed.
I'm not sure exactly what it's used for in the system. mrchill was concerned that the valve may get sticky as the car ages and he likes to give it a squirt of penetrating lube whenever a CR TDI comes into his shop. I thought it was worth posting as a maintenance heads up.
 

Pelican18TQA4

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Philadelphia, PA
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'13 Jetta Hybrid
The flap located downstream of the DPF and NOx filter is for the low-pressure EGR loop. Without the flap, low-pressure EGR is not possible. The low-pressure EGR loop does play a role in DPF regeneration, but it's largely for emissions compliance and is active to some degree just about all the time, even overlapping at times with the traditional high-pressure EGR loop. Everyone should read in detail the technical documents that are floating around on the web about the U.S. CR TDI :) So, moral of the story is, remove the flap and you've disabled the low-pressure EGR loop entirely and it will surely cause havoc with the other systems involved with the engine's emissions compliance, not to mention the DPF.

n1das, how many miles on your JSW? I'm curious because my '09 sedan had a hair over 40,000 miles when I traded it and I never heard a peep from the exhaust flap.
 

n1das

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2014 BMW 535xd ///M-Sport, 2012 BMW X5 Xdrive35d, former 3x TDI owner
The flap located downstream of the DPF and NOx filter is for the low-pressure EGR loop. Without the flap, low-pressure EGR is not possible. The low-pressure EGR loop does play a role in DPF regeneration, but it's largely for emissions compliance and is active to some degree just about all the time, even overlapping at times with the traditional high-pressure EGR loop. Everyone should read in detail the technical documents that are floating around on the web about the U.S. CR TDI :) So, moral of the story is, remove the flap and you've disabled the low-pressure EGR loop entirely and it will surely cause havoc with the other systems involved with the engine's emissions compliance, not to mention the DPF.
Exactly why I say don't eff with it. Leave it alone but give it a shot of penetrating lube once in a while when you're under the car.

n1das, how many miles on your JSW? I'm curious because my '09 sedan had a hair over 40,000 miles when I traded it and I never heard a peep from the exhaust flap.
Currently at 16k miles on the JSW TDI. :cool: Zero problems. The exhaust flap sound has been noted by me since day one. I think mine is no louder than in any other CR TDI. I thought I noticed being quieter right after mrchill lubed it when I was at his shop. It might just be placebo effect. Anyhow I agree with mrchill's recommendation to lube the mechanism once in a while with a penetrating lube spray as preventive maintenance.
 
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nownew

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Nov 6, 2010
Location
Michigan
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2010 Jetta TDI
1, can we ask the dealers to do it? I mean lubrication. Since 2010 TDi is under warranty.

2, My TDi makes noise like "wu~ wu~ wu~ wu~ er/wah~" every second at speed 70mph. Some guy suggests it could be from this valve. Any idea if it is true?

Thanks.
 

nhdoc

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'01 GLS NB TDI 5 Speed
I'd have some concern about using any lube in there which would cause dust and dirt to stick to it, as most do. It's possible VW explored the concept of lubing this but elected to keep it dry instead. Maybe just compressed air and brake cleaner to blow dirt out is better than using something that acts as a dust catcher, and especially using lubes where exhaust temps get hot enough to ignite could cause issues too. Just my $.02.
 

740GLE

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good point about dust/dirt, maybe that's where a little dab will do you, not need to go crazy under there.

As for the flamibility of penitrating oil/lube, I'd imagine by the time the cars off the lift and your echaust temps rise to combustable levels, most of the flameables will be well evaporated by then.

If you're really concerned about it, they sell antiseize compounds good up to 1800F (copper based). Maybe thats what's in there from the facorty and reapplying with it vs PB Blaster would be the best.
 

JosephH1

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Oct 29, 2009
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Lewiston, NY
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2010 Silver 2dr
Mine has recently failed, (45k) and upon removal, it appears the problem is more a bearing failure, the inside of the valve was relatively clean and very little crud came out of the bearing/shaft area even with solvent and heat. My was frozen solid, and heat loosened it slightly, but as soon as it cooled it tightened back up. Tolerances are tight and there is little opportunity for crud or penetrating oil to work its way in with the present design, but I don't think it will hurt. I will be spraying the new one at every oil change going forward. The dealer has 5 on back order, this is a common problem in Buffalo and a big money maker for the dealer.
 

specsalot

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Florida
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Be careful with PB, IIRC it's an acid, little or no lube value. (PB Blaster right?)

EDIT - Found a can at work:
Aromatic Hydrocarbons, Petroleum Distillates, Surfactants, and CO2 propellent. Don't know where I got the acid idea from. Worked on a chemical tanker over 5 years time (hauled merchant grade phosphoric acid), one of my subordinants swore by a dilute solution of phosphoric acid to bust bolts - He probably told me PB was dilute phosphoric acid.... DUH-RTFC-Kind of like RTFM :)

Can't image what a valve costs. The 'unobtainium' spare parts for the power valve on my R1 exhaust listed for over $1000.
 
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JSWTDI09

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I'm not sure exactly what it's used for in the system. mrchill was concerned that the valve may get sticky as the car ages and he likes to give it a squirt of penetrating lube whenever a CR TDI comes into his shop. I thought it was worth posting as a maintenance heads up.

What does the exhaust flap (valve) do? Read this post: http://forums.tdiclub.com/showpost.php?p=3739503&postcount=13

...and yes, if it fails (gets stuck) it will generate a CEL.

Have Fun!

Don
 

hotpocketdeath

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Suwanee, GA
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I'd have some concern about using any lube in there which would cause dust and dirt to stick to it, as most do. It's possible VW explored the concept of lubing this but elected to keep it dry instead. Maybe just compressed air and brake cleaner to blow dirt out is better than using something that acts as a dust catcher, and especially using lubes where exhaust temps get hot enough to ignite could cause issues too. Just my $.02.
I'm inclined to agree. Spraying a liquid lubricant in an area where a lot of dust and debris is going to be is asking for a clogging.

Personally, I would go the route of using a brake cleaner/air to clean it out first. But with the addition of using a "Dry" lubricant. You can pick up graphite powder from any hardware store that handles key/locks since it's primarily used to lubricate locks.

http://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=graphite&storeId=10051
 

n1das

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I'm inclined to agree. Spraying a liquid lubricant in an area where a lot of dust and debris is going to be is asking for a clogging.

Personally, I would go the route of using a brake cleaner/air to clean it out first. But with the addition of using a "Dry" lubricant. You can pick up graphite powder from any hardware store that handles key/locks since it's primarily used to lubricate locks.

http://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=graphite&storeId=10051
mrchill used penetrating lube spray when he gave mine a squirt. It essentially has the same effect as a "dry" lubricant since the volatile distillate fractions in the penetrating oil mix evaporate quickly. I would never use plain old motor oil because the assembly would remain "wet" with oil and pick up dirt & crap.

Brake cleaner followed by a dry lube is a good idea. :cool:
 

epc

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Jul 2, 2010
Location
NJ
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2010 Golf TDI
After 61k miles, my exhaust valve just went bad:

001151 - Exhaust Pressure Control Valve
P047F - 000 - Stuck Open - Intermittent - MIL ON

Not looking forward to spending $600+ to have this part replaced.
 

gumaku1

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Ohio
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2010 Sportwagen TDI - DSG
lubing it may just attract more dust/dirt, how do we know if lubing it is the best option? And what lubricant would you use? Penetrating oil evaporates easily, therefore would not have much benefit in the long term. Also what temperatures does this mechanism see under normal use? There are alot of things to consider before just making a general statement to "lube" the exhaust valve mechanism. I would like to see what VW's official service/maintainance procedure is on this valve.
 

740GLE

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i used WD-40 at my 40K service, I haven't sprayed anything for the past 16K, I'll probably spray it again at 60K.
 

scdevon

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USA
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It's a good idea to lube this valve, but "heat valve lubricant" should be used. Heat valve lubricant is graphite-based and its designed to lubricate moving parts on exhaust systems. The oil based carrier quickly evaporates and the graphite film is left behind.

GM markets a really good heat valve lubricant.
http://www.merchant-automotive.com/heatvalvelubricant.aspx
 

TDI_Timmy

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Feb 13, 2011
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Seattle
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2012 JSW, DSG, Pano
I understand that this thread is about lubing the valve - but had a question about operation and wasn't sure about posting a new thread.

So, I first had a 2011 Jetta TDI sedan with a manual trans and whenever I shut off the engine I never heard the "chunk chunk" sound. I feel that I am pretty in tune to the sounds of my vehicles as when I turned off my new 2012 JSW (DSG) I immediately heard a "chunk chunk" sound as soon as the key was moved to the OFF position. I am guessing this is the sound of the exhaust flap - correct? However, whenever I hear the "chunk chunk" sound I hear it from in front of the dashboard, right in the middle.

Lately I have been hearing a loud crash sound or loud metal snapping sound from under the vehicle. It isn't a continuous or multiple pinging sound - just one loud snap - and never heard it with my previous TDI. This sound happens about 1-3 minutes after shut down sometimes. Just have been waiting in vehicle when I have heard this. Thinking it has more to do with contraction of cooling exhaust pipe. Tried doing some search and must not be using right terms, but recalled reading this thread a few weeks ago.

Thanks in advance, and I apologize if it is slightly OT.
 

JSWTDI09

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sgoldste01

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I found the same thing. I think the parts department of your local GM auto dealership will be your best bet.
 
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