milkshake = headgasket.

When you say 'serviced the head' what did that entail?

If it's still doing afterwards it's probably warped the head..did you run a straight-edge over the block mating surfaces?

Headgaskets blow after running engines too hot or from inadequate torque on the head bolts. When stuff gets hot, things can be permanently damaged, like warped head. This can sometimes be fixed with a shave in a mill, but it's more easily fixed with another head.

It might be a blown oil seal in the turbo.
Clean the intake piping in hot soapy water, put it on and go for a drive until it smokes again. Check for oil in the piping.

Good luck,
Chris