Please tell me it's not the head gasket - 2013 VW Amarok TDI420

[Sharkie]

Cheaper than a head gasket?

Thanks Sharkie, do you know if there's a way to test/eliminate it as a possible cause? Some way to isolate the turbo?

No way to isolate whilst still fitted and part of the system I'm afraid. If you disconnect the coolant feed to it (which is what you'd need to do to test the theory), it will overheat very quickly and then fail catastrophically.

The only way realistically is to remove and visually inspect I'm afraid.

EDIT: actually, inspecting the coolant lines to and from the turbo may help. You'd need to remove some of it and inspect the insides for the soot you mentioned. I don't have the TTDI so can't help specifically. I could be totally wrong and the turbos could be oil-cooled only. That said, I have personally experienced this on a watercooled turbo before.

Perhaps have a look on ERWIN (Volkswagen AG erWin Online ) for scematics of the the turbo and its components. If you do, download everybit of documentation they have as it is all very useful and you never know when you may need something from it.