It's either coming in through a failed head gasket, blown oil cooler, or blown intercooler. My money is on the oil cooler, I've had one fail on me once. Granted it was probably due to me leaving water in it and leaving it in my garage (disassembled) over the entire winter. But they're easy to diagnose. Drain your coolant, disconnect the oil cooler lines. Plug one of them up, and apply pressure to the other side. If it holds 5-10psi, it's not the problem. Don't over pressurize it, like don't put 90psi of shop air to it. If you need an idea on how to build a pressure tester, let me know.
To remove all that water from the oil will take quite a few oil changes. If you have any good clean used oil, I'd pour that in to soak up the excess water. I had to change it 4 times, then perform the Boil-Out procedure. It's where you block off part of the oil cooler and run the engine on the hose for a while. Careful, it is a good way to cook your carbon seal if you're doing this in the driveway. Also, you can't run it very long in said driveway because of the closed circuit cooling system. You must be in water for the heat exchanger in the ride plate to work. The boil out procedure is listed in the repair manual.
