some coolants are green and some are kinda orange looking. It could be the coolant you are currently using. But if it is rust what you see, you should do a coolant change and hose out all the rust that there is inside your hoses and radiator. Hopefully you dont need to replace your radiator. When was the last time that you changed it? Do a search on how to change coolant or if you are too lazy, take it somewhere to get it done.
when i pule dthe head off my last motor the jackets all looked clean inside and the fluid that came out if it looked like a rust/ really dark brown color i was then informed that that was a normal thing that the toyo fluid is a dark red. then i bought it and sure nuff it was a dark color so i can see a bit of use woud muk it up
i should of add this earlier but i forgot. this motor hasnt been running for a while cuz im going to do a motor swap on my NA and right im just changing some gaskets and few other things. so this might help