Should the radiator be change out if the temperature gauge indicating a little over 50% 2001 astro van

OK, you're talking about temperature gauge dial on your dashboard? If it's running in the middle and not climbing into the red zone, you're fine. It's when you see it continually rise up and go into the danger zone. Remember, this is an appropriate reading of your cooling system. How old is your radiator and do you see any signs of leaking? And, how about your themostat?

NO.. BUT I WOULD ADD SOME RAD FLUSH/CLEANER TO IT AND DRIVE IT FOR AN HOUR..DRAIN IT AND REFILL..

Rust?? Where do you live? Is this a beach car?

I would try a Super Radiator Flush before getting a new radiator but that is up to you to decide if you have the funds of course get a me radiator.

If you decide to put in a new radiator I would do what Kelly suggested run a flush through the cooling system first to clean it out before installing a new radiator.

So, if it's not leaking, why change the radiator?