dmlanger

Any TDI owners have any Chemical Leaks? Today i discovered there was damage to my concrete floor in my garage. I park the car in the garage every day and back it in. Near the back right of the car i noticed there was some white chemical that looked like it was corroding away at the concrete. Its about 6x12 in size with a whole 3x6 in size and about 1-2" deep. I did a little bit of research and it was suggested that it was some kind of an acid. From what i gathered it could be the Adblue leaked out and all of the water in the adblue evaporated, leaving behind a highly concentrated Urea Acid that eats away at the floor. Anyone else have an issue like this? I dont keep salt, fertilizer or any chemicals other than gas for my lawn mower and extra engine oil in my garage so i've ruled it out to a chemical leaking from the Audi. Here's a picture. https://i.imgur.com/c24gNcK.jpg

tenspeed

Sprinkle it with water and add some baking soda. If it's acidic, it will bubble as it is being neutralized.

Cover the area with a old welcome mat, floor mat, cardboard, etc. until you find where it's coming from.

tenspeed

I was looking at the Audi 3.0-liter V6 TDI pdf for the TDI engine and came across the section about AdBlue
( http://vwts.ru/engine/cata/pps_94180...system_eng.pdf page 77):


"Reducing Agent AdBlue®

An extremely pure, transparent 32.5% urea/water solution is used as reducing agent, which is marketed in Europe under
the brand name AdBlue® and in the U.S. under the designation Diesel Exhaust Fluid AdBlue®.

The reducing agent is non-toxic, non-combustible, biodegradable, and categorized in the lowest water hazard class. It is
not a hazardous substance or hazardous material.

Reducing Agent Properties

– It freezes at 12°F (-11°C)
– At temperatures of approximately 158 – 176°F (70 – 80°C), the reducing agent decomposes and there can be
objectionable odors due to the development of ammonia
– Because of its unpleasant odor, aged reducing agent can be distinguished from the fresh solution, which is nearly
odorless
– Aged reducing agent or other foreign material added to the tank is recognized by the NOx sensors in the exhaust
system
– Escaping reducing agent crystallizes forming white salts
– The reducing agent has a high penetration ability and reaches the narrowest spaces due to the capillary effect

Reducing Agent AdBlue® Handling

– Use the reducing agent AdBlue® released by Volkswagen/Audi according to Volkswagen standard and DIN 70070.
Foreign media can damage the DeNox system.
– Do not reuse drained reducing agent to prevent impurities.
– The reducing agent should be added to the tank using only the released tools and containers specified by the
manufacturer. The tank cap of the AdBlue® active tank can be opened using the lug wrench from the tool kit."

dmlanger

Thanks for that suggestion. It did bubble as it reacted to the baking soda and was able to clean it up in about a half hour. Now i just need to patch up the concrete.

In fact from your suggestion I came up with a method to find the actual leak. I put some baking soda / water in a spray bottle and while the car was up on the lift, i sprayed in small areas near the suspected area, until i saw it react on the car and voila found the leak.

dmlanger

Thanks tenspeed for that info.

I'm sure it is 32.5% when it goes in to the tank, however after it leaks out, the water can and will evaporate to a much higher concentration, especially if the cars hot exhaust pipe is parked over where it dripped out and radiating heat.

I can confirm it crystallizes forming white salts and has a high penetration ability.

tenspeed

Glad to hear of your success. Frankly I was surprised that the leak caused so much damage to concrete. Perhaps TDI owners should apply concrete sealant to prevent craters.