Drain points for DEX-COOL in ZR409

[Infinity]

I want to change out the DEX-COOL this winter in my 2014 ZR409 "partial full" closed cooled system. I figure its time and its recommended every 5yrs anyway.

Trying to confirm all the DEX-COOL drain points so I can get it all out to replace with fresh coolant and don't see any diagrams for this in my manual. I assume that the drain points would include:

*Removing the knock sensors to drain the engine block
*The hose at the engine circulating water pump pipe
*The drain plug at heat exchanger
*Remove the 2 heater hoses
*Remove hoses to the overflow bottle

Am I missing anything obvious.....and does anyone have any clue approx how many gallons the system takes to re-fill?
After draining and before filling with new coolant, is there any way to "flush" it just to make sure that any potential debris/scale from the coolant loosing alkanitity? Or maybe easiest to just use a shop vac at each drain point to remove everything possible when its draining and/or get an extra gallon to pour thru system to flush before reinstalling the plugs.

Appreciate any tips

[j2nh]

I followed a similar plan with my 409 and it worked well. Impossible to get everything but you will get a majority. Key is to try and keep from making a mess, keep antifreeze away from carpet.

I can't remember how much it was but it isn't a ton, couple gallons if I remember correctly, then just keep an eye on the overflow when you put it back in operation.