I had already tightened that nut, and also checked once again the squared gasket, all good.

Today a drove a few kilometers, but since I see oil dripping from the joints along the muffler line, just a few drops, that would lead to think to a turbo failure, right?

However, I would not see the connection with the oil coming out from the filter.

Since the turbo sounds and appears to run well, how do I check if there is a failure in it?

I resolved the coolant leakage, which proves the head gasket was creating it, and now I get oil everywhere.

After 6 weeks, I am exhausted, and I need the car, so I think I am going to see a mechanic, put the car on the hoist and see if they can better see where the oil leaks.

Sad but true.

Alessandro