Planning on flushing the system and adding engine Ice this weekend. Looked at the manual and it says to just fill to cap. Also says to flush it 3 times running engine each time with 50/50 fresh water and coolant flush? Is this necessary or can I just flush it once with distilled water?

 

I just pulled one of the rad hoses, rigged up the garden hose, and just flushed it that way.
Allow the coolant to drain and refill with your desired anti-freeze.