Draining the coolant:

[WOW_FCTR]

There is a clever and very nice radiator drain incorporated into our radiators. The lower mounting "post" on the RIGHT side of the radiator doubles as the drain tube and there is a petcock valve directly above this point on the radiator tank. The coolant drains out of the absolute lowest point on the radiator and does not flow / dribble all over the lower structure of the vehicle.

To refill:
Filling is done via the expansion tank. There is a recirculating bleed-off to the pressure tank from the water pump that will extract all the air from the system. Fill the tank to the expected level with the engine off and let it gurgle down. Start the engine and let it idle while you add enough coolant to get your desired level. Cap it and you should be good-to-go.