Audi A6 C7 v6 3l black hard mass around exhaust manifold

[AurelijusG]

Hi

Hope someone has some ideas and can help me with the below please? 

Audi A6 avant c7 v6 3L TDI

I have noticed a black splatter around the coolant  reservoir  and top engine cover. Upon further inspection noticed a black mass of more of the same around where exhaust is coming out of the engine.  It is totally solid/hard. What is that? Engine runs ok apart from very rare juddering on cold start and some coolant disappearing overtime. (Like 200mil over a month or two) No leaks of any sort noticed

This black hard mass looks worrying 😞

No loss of power, no overheating, coolant reservoir nice and clean, oil cap clean, no bad smoke coming out of exhaust- none of the worrying bits if you know what I mean? 

Any help would be much appreciated. 

See pictures attached.