Something leaking?! Pics inside

While refueling I did the usual under hood check, and found some white build up on a plug/sensor on top of what I think is the DPF. The build up is white, fluffy crystallized ... almost like coolant buildup, but the only think in that area I could think of would be Urea/AdBlue injection into the system?
The corrugated hose goes down into the shaft where the 2x diesel fuel lines go...

Any thoughts?

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I think the sensor is leaking and I would take it to the dealer for warranty repair ASAP.
I wouldn't care what it was unless it is toxic. If it is ash leaking then it might well be toxic.
Part of the emissions system should be warrantied with a 2015 Golf.

That appears to be def leaking from the sensor or connection. When the water evaporates it leaves the urea which crystalizes. Should be covered under warranty.

A cut and paste portion from an article about DEF in truckinginfo.com

"The air will evaporate the water, and urea crystals will begin to build a chain. This will typically happen in about 30 minutes. The crystals will find even the smallest path through connections, especially threaded connections and seal areas.

How do you prevent "DEF creep"? Make sure all fittings that come in contact with DEF are tight and proper seals are used. Try minimizing breaking connections and wipe down any urea crystallization as soon as it forms.

Water can be used to easily wash off urea that has crept onto the truck, tank or dispensing equipment."

Your car has kidney stones

I will second that as I have read another thread on the same issue.
Side note; do you smell exhaust when you first start the car?

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JASONP said:

I will second that as I have read another thread on the same issue.
Side note; do you smell exhaust when you first start the car?

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I do.

JASONP said:

I will second that as I have read another thread on the same issue.
Side note; do you smell exhaust when you first start the car?

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Not that I can recall on the smelling exhaust question.
I called my SA yesterday morning and got an appointment next week... We'll see. Def looks like DEF fluid to me as well... Really wish we had some diagrams of the DPF/emissions systems specific to this car, as the self study guide doesn't have the emissions system, has to be referenced from the passat?


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I cleaned it up the other day, after a few days the crystals have regrown. Car wash(service appointment) is scheduled for Thursday ...






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that is clearly crystallized DEF

As that is the DEF injector, I would say there is a very high probability that the crystals you are seeing are coming from a DEF leak. Coolant leak is another possibility since the injector has coolant flowing through it. I believe the two lines you have seen plugging into it are the coolant lines.

TurboDieselPoint

Can't complain about the loaner.





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SA called and advised they have ordered a replacement DEF injector and feed hose. Maybe in tomorrow.


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Injector assembly was replaced. I'll keep an eye on it and report back if it leaks again.

Any more leaks with the new assembly?

I just found the same issue on mine (pic below)... Did you get any feeling from your service department on whether this is a serious problem, or how common it is on DEF TDIs (i guess just Golf and Passat at this point?).

It seems like a very small leak could result in what appears visually as a lot of crystallized urea, but might not make a big difference in the overall DEF level or operation of the system. I'm just trying to determine whether I'm willing to go ask for a fix that i'm not sure will even work, if it's not a huge problem.

I'd encourage other people on this forum with Mk7s to check theirs and report.

Mine is good, so far.

andyrooski17 said:

Any more leaks with the new assembly?

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Checked today, and looking good - no signs of leaking with the replacement.
That said, I haven't driven that much lately, I'd have to look at the service order, but probably around 1,000 miles or less since the replacement assembly was installed.

Just had mine replaced: reported in the Common Issues sticky thread.

Fingers crossed no more leaks!

WiszMaster said:

Checked today, and looking good - no signs of leaking with the replacement.
That said, I haven't driven that much lately, I'd have to look at the service order, but probably around 1,000 miles or less since the replacement assembly was installed.

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I'm at 11,400 miles now, a little shy of double the miles from when the injector was replaced, and it's still spotless clean. No leak, the updated part seems to have resolved the leak for me.

I just hit 20,000 miles, and no recurrence of the issue at this point!


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Same here, just had 10k service, still looking good. Seems that there are some bigger issues with the AdBlue system being reported in this forum...

Mine just started to leak after 24500KM. I'm currently 2500KM from home. Seeing the dealer will have to wait a bit...

adblue leak update

Had my 2015 golf in for service over the weekend for 50,000 miles. It was discovered that my adblue injector feed line has a crack and is leaking. After leaving the dealer (line not repaired) my CEL came on and I had a message saying adblue was low 500 miles until empty...
I questioned service if they topped my adblue tank off, it was explained to me that the leak will cause my car to think it is low on adblue even though the tank is full. Also the leak will cause the CEL to come on.
For those that do not know a full tank of adblue should last somewhere between 10,000 and 12,000 miles (at least this is what i have seen). If your lights on and you are not near that mile mark it is possible that you have a leak. If you don't have a leak and you are low on adblue you have to put a minimum of two 1.89L bottles in the tank for it to regester.
Either way parts are ordered and my car is being dropped off for repairs in the morning. Hoping for a quick turn around and no additional issues!

Just checked mine, its clean.

Same Problem

WiszMaster said:

I cleaned it up the other day, after a few days the crystals have regrown. Car wash(service appointment) is scheduled for Thursday ...

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I had the same problem and took the car in to the dealer with 55K on it. VW declined to pay saying it wasnt part of the emission systems covered until 60 K. Serioulsy

Good for the dealer, love it when they get creative. Did you get the "fix" if so point to the literature.

If you don't have the fix, they are actually right the normal fed warranty on that part is only 24 mo/24K or something ridiculously low.

Tell it to all the people who changed out their passat adblue heaters

I have the same issue on a 2015 Passat TDI. The Add the AdBlue light came on and I was surprised as service was just 3 months ago and AdBlue was topped off. Then I opened the hood and found a large clump to white crystals in the same place. The car goes into service in the morning.

best of luck, report back how the dealer handles it.

Adblue error

My 2015 Passat with 84000 kms had the same issue yesterday. I have a huge crystal ball under the hood and the adblue error warning came on and the check engine light. It’s the weekend so I’ll call the dealer first thing Monday morning.

Technical Bulletin 26 16 02 March 31, 2016 2039436

Technical Background
Welding process issues of the reductant line connector to the supply line may cause AdBlue® leakage at the reductant injector.

Production Solution

Improved parts implemented into production.

Service

Inspect the connection of the reductant supply line connector at the reductant injector in the engine compartment.

If white crystalized (dried) AdBlue® is found at the reductant injector (see Figure 1 & 2), it will be necessary to replace the reductant supply line.

Thoroughly clean the area of the reductant supply line connection with water to remove the crystalized AdBlue®.

Replace the reductant supply line.

It is not necessary to replace the reductant injector

Required Parts and Tools

Model Part Number Description
Passat 561 131 984 D Supply Line for Reduction Agent

Golf, Golf SportWagen 5Q0 131 984 E Supply Line for Reduction Agent

Jetta, Beetle, Beetle Convertible 5C0 131 984 B Supply Line for Reduction Agent