Is there any signs of coolant in the oil? Should look like a milkshake. Check the underside of the oil fill cap as well.

Sounds like your leaking coolant around the TB due to the UIM being warped/cracked. If you haven't replaced the LIM gaskets it would be a good time to do that as well to avoid future issues. ineedparts.com sells a good kit for the UIM that includes everthing you would need to do the work. Been running mine for over a year and no issues.