Where is the valve to empty the radiator?

I'd strongly advise against opening the drain in the radiator. It was really common for the O-ring on the plug to become cut and/or the plastic it seats against to break, then there would be a drip about once every five seconds. The manufacturer that supplied these radiators to Chrysler may have changed the design since the mid '90s, but it isn't worth the risk. Instead, it is much easier and faster to disconnect the lower radiator hose.