Best to drain the radiator and then put a drip pan under the lower radiator hose where it comes off the water pump. You will lose about a cup or two after the radiator is drained. Doing it without draining the radiator will lose a gallon.
Mine had a drain on the driver side of the radiator I was able to open and drain it was slow but less messy than opening lower radiator hose.
I had high miles so I replaced the several things the plastic housing in front of motor I heard sometimes cracks doorman makes an aluminum one that I replaces as well as the heater hoses with again a doorman unit that makes an aluminum t fitting for units that have rear heater core as well.
Today is day after the radiator and thermostat replacement. The overfill tank line was a little loose (and leaked out after driving) so I placed a small hose clamp and it appeared to do the trick. No leaks.
Filled up the radiator some more per the recommendations of others and the car ran consistently right below the middle on the temp gauge, which reassured me that the van had either: (1) failing thermostat; (2) old coolant that needed changing; and/or (3) leaking radiator. I’m guessing it must’ve been the thermostat.
Before the repairs, the van was consistently few lines below the middle and my gas mileage was horrendous.