I understand the part where you drain out the old radiator fluid then add water then run it and then start adding the flush cleaning solution. But what I am confused is do I leave the radiator cap off when I do this or do I add the cleaning solution in the overflower while it is idling?

 

You pour in radiator... fill rad... put cap on.... run for how ever long it says... then flush out...

 

Make sure if you are doing the home flush, which I assume you are, that you get all the tap water out and fill with Coolant and distilled water only... But, Im sure you know that... right?

 

a bit of tap wont kill your radiator if theres some left in it

i used to add tap to mine all the time wheelin when it would leak out and get low on fluid, but if you can get distilled or just 50/50 mix then go that route

 

.....but u could also pour 3-4 gals of distilled water in to flush the tap water out.......about 50 cents/gal.

 

My neighbor came over to help me I did not ask he just came over then ended up helping me.