if it has been along time since you flushed it out, then it will be brown/rusty colored
How long since you last flushed it??
So if I understand correctly you put in the radiator cleaner drive 3-6 hrs. Then drain it and restore normal coolant?
Yeah I already replaced the t.stat. I'm gonna give this flushing a swirl.
Oh yeah and I'll go back to kindergarten to learn proper grammar