Need some help with Coolant issue in 2002 Tiffin Allegro

don't mess with adding antifreeze drain the system there should be a drain on the bottom of the radiator there is a block drain near where the turbo oil drain goes into the block it is a bolt with a copper washer (don't drop the washer it can be reused refill with EIC anti freeze run the engine to operating temp to purge the air also turn the dash heater to full heat to get the weak antifreeze properly mixed