Radiador 2001 chevy blazer 4x4

I need to know where the flush valve is located to flush my radiador?

There is no such thing as a “flush valve”. Are you thinking of the petcock perhaps? It is a wingnut looking thing somewhere along the bottom of the radiator. If you are trying to drain and refill the radiator, removing the lower hose will get most of the coolant out the radiator.

Some vehicles do not have one.

Drain valve should be on the lower left. If you see a little rubber hose pointing up, the valve is on the other end of it. You lower the hose and open the valve to let it drain.