My only issue with the procedure in the posted PdF s relates to the coolant trapped in the heater core. How do you get old coolant out when engine is off and cold? Are any check or control valves open so it can drain by gravity with the engine coolant? Also how are you supposed to refill the heater core with new fluid? Are you supposed to set the dual climate control to a high temperature to allow it to enter the heater core? The Toyota instructions say nothing about this.