I would smoke test the exhaust system to find the leaks. On my '09 CATA it was the turbo that was causing this issue, but could be any number of things.

 

Were you able to get a warranty repair on that or did they insist on seeing a code ?

 

Could be many things. Downpipe. Turbo. EGR.

 

Sounds like you have a small exhaust leak... Pull the back turbo heat shield off and look around on the down pipe, upstream EGR cooler piping and mount hardware. Also check on the manifolds, gaskets, or piping.

Also check your injector weep hole. VW made a nice cross drilled passage to the external side of the head above the exhaust manifolds. Check the little weep hole below each injector above the manifold bolts. If you have exhaust soot - fuel mix the copper compression seal on the bottom of the injector is leaking and causing your cabin exhaust smell. Resealing the injectors and cleaning the injector holes is a easy job.

 

I experienced this too.

 

Thanks so much for the suggestions, but being unfamiliar with the layout of the CATA in the Touareg many of these parts are a mystery as to where to look. My previous experience was with a hundreds of thousand miles on the 2.0 TDI in a couple of Jetta Sportwagens.
I see a black greasy stain on what looks like the right motor mount, but I can see much about it without my ramps that currently live in the next state.
I think that I will try the USB camera at the end of a cable to see what I can see with that gizmo.
The visiting kids are heading back home tomorrow and prior to Christmas both the wife an I have been under the weather for a while.
The smell is not an every day thing (so far).
I wonder how to do a "Smoke Test" on the exhaust. are there any suggestions for generating the smoke and the pressure?
Thanks again,
J.D> Barron

 

To do a a smoke test you need a smoke testing machine/device to generate the smoke, and need to block off the tailpipe.

search Amazon for “Automotive Smoke Machine Leak Detector” it should be under $100

 

I looked up the available smoke leak test machines on Amazon and they can be purchased for less than paying for the test (according to the Googles cost for the test).
My question would be do you plug one of the exhaust pipes at the rear and introduce the smoke in the other and let the low pressure work it's way to the front of the vehicle, or is there a readily accessible port or hose that you can out it in from the top, over the engine?
It would seem that since the smell is not always present it could be part of the system that is controlled by some valve, etc.
Any suggestions?

Thanks,

JD Barron

 

Can anyone tell me how difficult replacing the EGR pipe (as shown in a picture above) is to change?
The cost takes your breath away and I have not yet had a chance to take a look, but I am tending to think that this is the problem with my TDI.
I hope to get a endoscope camera to take a look at it for a crack in the bellows.

Thanks,

JD Barron

 

https://www.clubtouareg.com/threads/7p-cata-egr-delete-with-coolant-line-re-route-info.302573/

Difficulty depends on your skill level.

This info is for a full EGR delete. The pipe replacements are the first part of the delete. With that info someone that is a good technician can get the job done fairly easily. There are some parts of the job that can be ignorant though such as tight and hard to access torx bolts and positioning your self for access. Hope that helps

 

Thanks for the info.
I guess I am really wondering just where the EGR pipe (with bellows) that comes from the exhaust to the cooler and where the cooler lives.
My old brain has not yet made heads or tails from the pictures where this is located and how to get wrenches on it to replace the pipe.
I do have some experience (being an aircraft mechanic and AI as well as working on my older 2.0 TDI Sportwagens, but i haven't had a chance to plunder around the 3.0 and figure out if I need ramps or a lift to go from the bottom or if it can be changed from the top.
I will spend some time with the endoscope and see if I can eyeball the pipe and if I can get my 75 year old hands in to work or if I need to take the car to the dealer (Whhhaaahhhhh).

Thanks,

JD Barron

 

You need to plug the outlet to do a smoke test, and can get plugs that have a port for the smoke. It’s also likely possible to make something up yourself from a hardware store.

On my Touareg the smell was very intermittent but I think that was just because the amount of smoke actually coming into the cabin depends on variables like engine temp, driving speed, engine load, and wind conditions.

an Endoscope or even a small mirror sounds like a good idea.

 

I still don't have any real idea where these EGR pipes live. Are they around the back towards the right side of the motor?
Also with the smoke machine if it is pumped up the exhaust (the other pipe plugged, of course) will the smoke go past the EGR valve / cooler? since the smell is intermittent the crack in the pipe might be downstream of the EGR valve.
Also that pipe with bellows from the exhaust to the cooler is around $650!
Since my car was modified (dieselgate) at around 94,000 miles and now has 170,000 it will be my dime for the repair.
For those who have changed this pipe (assuming that this is the problem) how did you get to it? Can you get to it from the top or bottom?
I found a great reference on another post here and here is a link to the PDF file that helps me visualize the location and extent of the job.

https://www.clubtouareg.com/attachments/3-0tdi-gen1-egr-blockoff-guide-pdf.260718/

As I investigate I will try to add some pictures for those who follow.

Thanks all.
JD Barron

 

A picture is worth many words.

 

🧐

 

Here is a picture I found on eBay of what looks like a CATA 3.0 engine. I assume that the EGR cooler and the pipes are in the bottom center of this picture, under the down pipe, for the convenience in replacing. It looks like that to see it with my endoscope I will have to remove the turbo heat shield and look from around the back of the down pipe where it exits the turbo.
Has anyone been able to worry out the pipe(s) if one is cracked?

 

Yes bottom center is EGR and cooler

 

I looked as best as I can at the visible part of the EGR pipes with my endoscope and I could not see any cracks in them.
Of course the view is very limited with the heat shield in place.
I will see if I can remove it Monday and get a better look. It looks like it will still be hard to inspect with the exhaust down pipe installed.
For those who have replaced an EGR pipe, how difficult is it to get to? Did you remove the down pipe? [ I did see a You Tube video on an EGR delete and in that video the down pipe was removed and pushed to the rear for access, so perhaps that would work for inspection and R&R] How did you get to the Torx bolts? (or are they the famous trisquare).
Of course I can hear no exhaust sound from anywhere.
As a side note it seemed that after a refuel towing our 16' Scamp we had a faster drop in fuel gauge readings and then we had the smell.
It is hard for me to tell the difference in untreated exhaust and diesel fuel, but so far I have not been able to find a fuel leak or seepage.
Any further ideas would be appreciated as I hate to take this car to the dealers to "troubleshoot" and open my wallet for a depth check and limitless billing to replace expensive parts til maybe fixed.
Perhaps if it is an exhaust leak it would be time for a delete as an EGR pipe is a fairly high percentage of that process.

 

These things can be tough to track. If it's truly exhaust and not a leaking injector, the pressurized smoke test should help diagnose it.

A depressing anecdote... mine is still under warranty, and it's been to the dealer 20+ times since 2020 for the same issue (diesel exhaust in the cabin). What I'm aware that they've replaced:
8 injectors and associated lines/seals
turbocharger
downpipe
4 exhaust manifolds
up-pipe
EGR pipe
multiple "leaking" DPF sensors
many things in the valley + oil cooler

I suspect the issue is the EGR cooler, but I'll continue depreciating the loaner Atlas and letting them throw parts at it until VW decides to buy it back (in the works). It's been in the shop with an unsolvable diagnosis since early September.

 

8 injectors and associated lines/seals

Since you have a V6 TDI and they added\replaced 2 more injectors than it uses, I would suspect that is the issue with the smell of diesel.... two injectors are firing into the engine bay 😇

 

I certainly hope that the smoke generator and test will show where the leak is - Hope springs eternal!

 

The smoke generator came in yesterday and I blocked off one of the exhausts and pumped the smoke into the other. The smoke tester I used is said to generate smoke up to 16 PSI and it could push no smoke out any leak that we could see.
We could smell it a little (scented baby oil), but could not see anything.
I did have the endoscope out and looked at the suspected hot side (upstream) pipe from the turbo to the upstream cooler. No smoke, but a suspicious black stain in the last corrugation where it is most bent.
Here are some pictures:

I suspect that the crack is closed when cool and no exhaust pressure and there is not enough "crack" for the smoke to come all of the way from the exhaust pipe to this spot through the mufflers, CATD, DPF, etc.
I could remove one of the sensors in the exhaust I assume, but I hate to generate some other issue there.
What is the general opinion of the discolored area? My thought is that there is an exhaust leak there under some conditions.
The replacement pipe is $648.00 plus gaskets. I assume that the downpipe from the turbo will have to be removed for access as well as the downstream pipe that blocks access to the bolts on the bottom of the flange on the turbo end plus new gaskets for everything.
Hs anyone done this already and can offer some suggestions for a 76 year old reformed A&P / maintenance manager tinkerer?
I am planning on buying a couple of really good T-30 TORX impact bits (I understand you wan one to be - LOoooong) so that they don't bugger up the bolts.
Thanks in advance for the help.

JD Barron

 

The smoke generator came in yesterday and I blocked off one of the exhausts and pumped the smoke into the other. The smoke tester I used is said to generate smoke up to 16 PSI and it could push no smoke out any leak that we could see.
We could smell it a little (scented baby oil), but could not see anything.
I did have the endoscope out and looked at the suspected hot side (upstream) pipe from the turbo to the upstream cooler. No smoke, but a suspicious black stain in the last corrugation where it is most bent.
Here are some pictures:

View attachment 262193



I suspect that the crack is closed when cool and no exhaust pressure and there is not enough "crack" for the smoke to come all of the way from the exhaust pipe to this spot through the mufflers, CATD, DPF, etc.
I could remove one of the sensors in the exhaust I assume, but I hate to generate some other issue there.
What is the general opinion of the discolored area? My thought is that there is an exhaust leak there under some conditions.
The replacement pipe is $648.00 plus gaskets. I assume that the downpipe from the turbo will have to be removed for access as well as the downstream pipe that blocks access to the bolts on the bottom of the flange on the turbo end plus new gaskets for everything.
Hs anyone done this already and can offer some suggestions for a 76 year old reformed A&P / maintenance manager tinkerer?
I am planning on buying a couple of really good T-30 TORX impact bits (I understand you wan one to be - LOoooong) so that they don't bugger up the bolts.
Thanks in advance for the help.

JD Barron

Man, 76 and still wrenching. I give you huge props. You're probably healthy as a horse too. Good for you man.

 

So clean the black off and see if it re-appears.
That's clearly a "flex" section, so it's quite feasible that it only "opens up" and leaks under certain movement\vibration\conditions. If you can get an inspection mirror into that area, start the engine and stick the mirror near it... it should fog up as soon as the leak "hits" it... or turn black, etc.

I don't think you'd be able to push your smoke back that far through all the muffler\resonator\DeNox Cat\DPF\turbo

Pull the temp probe out of the turbo, or something similar and inject smoke there if you want to "smoke test" using the machine.

 

You have options

Pull the temp probe out of the turbo

 

I assume this is the component you are "showing" us

 

I assume this is the component you are "showing" us
View attachment 262196

I think it's this part, from just below the turbo to the EGR Cooler which sits right above the part you highlighted.

 

My wife's 2015 TDI was in for the exhaust smell, sometime in the past 2-3 months ago and the exhaust manifold(s) were replaced under the extended(dieselgate) warranty.

 

Since you have a V6 TDI and they added\replaced 2 more injectors than it uses, I would suspect that is the issue with the smell of diesel.... two injectors are firing into the engine bay 😇

When they've replaced every cylinder, and then once again on two cylinders, you can just use simple arithmetic Funnily enough, one of their injector "repairs" resulted in diesel actively spraying all over the top of the engine.

And two extra manifolds..... what are those plumbed into? The 2nd turbo?

Same with both exhaust manifolds being replaced twice each. Though I'd probably be okay with a bit of exhaust smell if they were doubling up the turbos...

 

Sounds like they have a massive parts cannon