[cotbu]

there should be no oil in the hot pipe, if you think the turbo is leaking from the cold side, then check for oil in the intake manifold.
if there is? remove the intercooler, piping and manifold, and get to cleaning. the oil could be pooled somewhere and getting blown through the system.

Now, valve stem seals wont make the hot pipe have oil in it, but the exhaust manifold, turbo, down pipe etc. will.
Here pulling the exhaust mani can tell you, if it's the turbo or engine leaking oil. if there is no oil in the manifold then it's probably the turbo.

I would do a warm up, then shut down! let er cool down, hope for the easiest fix.