Club Touareg Forum banner

1 - 20 of 37 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1 (Edited)
Recently I found my tailpipes has been covered by white powder type residue. They used to be clean and shining always. I am very sure the soot is coming from inside of the pipe. Wondering what is going wrong. The vehicle is running without any noticable issue.

Sent from my Pixel 2 XL using Tapatalk
 

·
Registered
Joined
·
1,568 Posts
changed where you fuel up ?

Not salt ? where are you located ? Engine type and kms on odometer ?
 

·
Banned
R5 (2008)
Joined
·
1,159 Posts
Could be Adblue residue, especially if your pump has degraded or your fluid is old and started to crystallize, and the pump spray can't atomize the fluid properly anymore. If your Adblue refill was quite a long time ago it might possibly make sense to refill it now with some fresh good quality one, which could possibly remedy the situation.

Or it could be coolant residue if it's leaking somehow into the combustion chambers (like through the EGR cooler). Obviously your coolant level should drop over time if that's the case. If it doesn't (drop), then you can exclude the coolant leak as a possible cause.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #6
Could be Adblue residue, especially if your pump has degraded or your fluid is old and started to crystallize, and the pump spray can't atomize the fluid properly anymore. If your Adblue refill was quite a long time ago it might possibly make sense to refill it now with some fresh good quality one, which could possibly remedy the situation.

Or it could be coolant residue if it's leaking somehow into the combustion chambers (like through the EGR cooler). Obviously your coolant level should fall over time if that's the case.
Thanks!

Sent from my Pixel 2 XL using Tapatalk
 

·
Registered
Joined
·
1,132 Posts
That doesn't look good at all. Can you use your finger and it all comes off? Or do you have to really scratch it with something to get it off of the pipe?
 

·
Registered
Joined
·
22 Posts
Discussion Starter #8
That doesn't look at it all. Can you use your finger and it all comes off? Or do you have to really scratch it with something to get it off of the pipe?
yes, it's white powder, I can easily wipe it off with my fingers

Sent from my Pixel 2 XL using Tapatalk
 

·
Registered
Joined
·
1,132 Posts
I'm wondering if it is Def related, as mentioned. Take it in let the warranty work. It's probably not operating correctly.
 

·
Registered
Joined
·
743 Posts
I have the same thing on my exhaust tips. The EGR cooler was replaced not long ago. I had never heard the DEF could be old. Can adding a little distilled water help?
 

·
Registered
Joined
·
2,266 Posts
Can adding a little distilled water help?
You'd only be diluting your good DEF..... don't you know when your tank was topped up last? Don't you know what your driving amounts are like? You were pulling a heavy trailer not that long ago, which means that would've had increased DEF usage, so very unlikely that you're on 1.5 year old DEF in your tank.
 

·
Registered
Joined
·
743 Posts
I top off every 3-4 months (@3K Miles). But it appears there is no seal on the top of the DEF tank so when full it appears to slosh.

I don’t think the white residue is from bad DEF (not sure chemically how the compounds would go bad except change in concentration) unless the concentration is to high which could be diluted by a small amount of distilled or deionized water.

In my case I suspect the emissions fix just runs DEF rich and the residue is exhaust ‘vapor’ condensate drying on the tips.

I normally wash them and it comes right off. Not a huge deal unless it means something is wrong.

Also it’s been quite a while since I’ve towed a large trailer. But I have an exhaust leak at the moment. Not sure if this messes with DEF use.
 

·
Registered
Joined
·
2,266 Posts
I'm sure an exhaust leak is not helping anything, as you're dropping temps, etc.
I find it amusing how some of you guys identify these anomalies only to later on disclose that you have known pre-existing issues and failed components....
 

·
Registered
Joined
·
743 Posts
It’s not a huge leak just enough to smell in the AC vent. Dealer has tried to fix it. Still can’t find it. I don’t think it impacts DEF levels unless it’s changing temps or A/F ratio.

I can’t help wonder if VW turns the DEF up and isn’t worried about DEF running rich as long as they pass emissions.

Is white residue on exhaust tips something a dealer is supposed to identify as a problem and troubleshoot or is it only when a customer complains?
 

·
Registered
Joined
·
2,266 Posts
Last time I checked, the DPF function depends on both pressure and temp deltas...... so any exhaust leak would allow both pressure and temp to "escape" pre DPF and related sensors.....

You need a better dealer, if they can't find a leak they are borderline useless.
 

·
Registered
Joined
·
743 Posts
How do I find a better dealer? Does VW have a list of TDI specialists that are super certified in root cause and troubleshooting of TDI problems?
 

·
Registered
Joined
·
2,266 Posts
No idea what part of the woods you're in..... but up here in polar bear land, we typically have a handful of dealers within a reasonable radius, so if the one you typically deal with is a gongshow, go try the next closest one.

Or if you live out in da stix, you may not have that option.
 

·
Banned
R5 (2008)
Joined
·
1,159 Posts
I have the same thing on my exhaust tips. The EGR cooler was replaced not long ago. I had never heard the DEF could be old.
It can not only get "old" and degrade (ie. loose or change some of its chemical and physical properties), but can actually crystallize, which in turn can totally clog the pump/spray, necessitating a complete replacement of the unit.

Can adding a little distilled water help?
No. For one, water won't "revitalize" degraded AdBlue the fluid, it will only make it even less effective and less of what it should be. Also, the AdBlue fluid is a very specific concentration of urea and distilled water already, and if you change that concentration is distrubed, your SCR will start acting up and you can get all kinds of fault. If you have the suspicion that your AdBlue has expired or is of low quality, the best thing you can do is extract the old fluid and refill the tank with high quality fresh fluid.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #19
I'm sure an exhaust leak is not helping anything, as you're dropping temps, etc.
I find it amusing how some of you guys identify these anomalies only to later on disclose that you have known pre-existing issues and failed components....
My car has nothing wrong, no cel, no fault code, no noticable difference except the new white residue from exhaust. I saw people complained same thing on Audi 3.0Tdi. Could be a common issue, my happened 20000 miles after diesel fix.

Sent from my Pixel 2 XL using Tapatalk
 

·
Registered
Joined
·
2,266 Posts
My comment was directed at someone else......

Regardless, you have sufficient milage that it's quite feasible that your DPF may be approaching the end of its life (lots of contributing factors).... if you're not noticing a performance degradation, I would just ignore it and simply deal with the "cleaning" aspect of it... you could try a different brand of fuel, or maybe even DEF fluid, to see if anything changes.

What are your driving patterns like?
Do you drive like a granny?
What kind of climate do you drive in?
 
1 - 20 of 37 Posts
Top