Why is my coolant rusty?

kursplat said
who would rebuild the motor and not clean the radiator? :rolleyes:

Certainly not me!! Haha.

Well, I "flushed" the radiator very thoroughly with water, but as @MoparLeo pointed out, I didn't do it correctly. I hit the block pretty good with brushes before assembly, so at least I have that going for me.