White stains on the road

[The swintonian]

Good afternoon all,
I recently purchased an A6 Avant 3.0 BiTdi
After returning from a 60 mile round trip on Sunday I parked up and noticed that I had left a trail of water that dried white very quickly in the sunshine. I assumed that it was condensate from the air conditioning but the white colour didn't seem right.
I used the car yesterday and had the same result when parking up after a 10 mile round trip.
I went to work today and there was no water trail when I parked up after a 14 mile trip.
When I left I checked under the car and it was bone dry with no white stain.
Upon returning home the Emissions Control light came on.
Anybody got any ideas what both these could be?
Thanks in advance.

 

[Mo-S3]

Does it take ad blue? Ad blue dries a crystal like white colour

 

[B5NUT]

I would agree you have an adblue leak. You will need to get the car up on the ramps to see where it's coming from.

 

[The swintonian]

Yes, it has adblue. I thought that it might be an adblue leak but you have confirmed it. A trip to the dealer is required then, it has a 6 month warranty so hopefully it can be done without any cost to myself.

 

[The swintonian]

I took the car into Manchester Audi today for a diagnostic check to find the fault so that they can tell the warranty company what needs to be fixed. They have had the car all day and I got a phone call at 16:30 to say that they needed to do some more tests because they had not found the fault yet. Fingers crossed that they find it tomorrow.

 

[The swintonian]

Well, after three and a half days in the dealership, I finally got my car back at lunchtime today. After doing a full day of diagnostics they said that they could not find any faults and needed another day to investigate further. I asked if they had looked for the AdBlue leak and was told that they needed to carry out all the diagnostic tests first for the warranty claim. They then sent me a video from underneath the car showing the massive AdBlue leak from the injector and associated pipe work which had left white stains virtually everywhere.
When did a description of the problem get dismissed by the “computer” says that there is nothing wrong mentality?
They obviously did a visual inspection of the car, I knew that all 4 tyres were close to the limit, and concluded that all 4 tyres needed replacing. I asked them for the price and they wanted £183.50/tyre for Pirelli PZero 255/35/R20 97Y. Audi do a price match on tyres and I found them at a tyre dealer very close to the dealership for £165/tyre with a £60 discount if you bought 4, total cost £600. They agreed to match that price. When I collected the car the price for the tyres was reduced to £499, what a bargain!