The drain plug is on the bottom drivers side of the radiator. It is a tough little valve to get at.

I did my dexcool removal a few weeks ago. I draind then flushed with water for several minutes. Refilled with water and preston super flush and ran it for a day. Then drained and flushed again. Did this 3 times.

I then used 1 gallon of 100% green antifreeze since there was water in the block that would blend with the straight antifreeze. The rest was filled with 50/50 green.