Hi guys. I am possibly going to do a radiator flush today and had a few questions I'd like to ask before moving forward with the procedure. I've searched and read through the following threads and I am still unsure of a few things.

https://www.scionlife.com/forums/sho...radiator+flush

https://www.scionlife.com/forums/sho...radiator+flush

https://www.scionlife.com/forums/sho...radiator+flush

From what I understand, the following procedure should be done:
1. Drain the coolant
2. Fill radiator and coolant resovoir with distilled water and allow the engine to run with the heater on for 5-10 minutes.
3. After the engine cools, drain the distilled water and repeat step 2 if necessary and drain.
4. Refill with recommended coolant.
5. Properly dispose of used coolant and distilled water.

How many times should i repeat step 2 and should i leave the radiator cap off when doing this step. What is the purpose of step 2? Thanks guys.