Hi does anyone know what this is? 

It's the 2.00 litre diesel

AdBlue?

 

 

Edited 21 December, 20223 yr by varooom
Additional Information

I didn’t know this was a thing but hopefully it’s just a hose or o ring.

 

Might be worth getting rid of all of it so it looks new, go for a drive or just let it idle and see if you can see the source before it builds up like that

Thanks for the info. Very helpful. 

Adblue injector or hose cracked - personally I’d replace both as they are fairly common.

 

remember the system should be purged once replaced else you may get a nox efficiency code appear after a few 100 miles 

I've just found the exact same buildup in ours (MY2016 TDI 150).

 

Had a couple of "Reductant pressure too low" errors recently, popped my head under the bonnet and immediately saw a huge clump of white crystals.

I guess when it stops raining I'll clear it all off and see if I can spot where it's leaking.

 

Anyone know how DIY-able replacing either the injector or hose would be ?