3RZ cooling problem - No flow

I recently purchased an off road crawler that has a 2000 3RZ 2.7 liter engine as determined from the engine id number. My problem is overheating. Digging into it, I flushed and checked all flow paths in and out of the radiator from the engine in and out paths. The thermostat was removed which leads me to believe this always had a problem. Installed the thermostat, no change, overheats and doesn't appear to flow through to radiator, located in the rear of the chassis. The radiator is all aluminum with electric fan. Pulled the water pump, looks good, but replaced it anyway. No change, no flow and overheats. When I look at the water pump the impeller looks like it should be rotating counter clockwise but the engine turns it clockwise. Both pumps new and old have the same impeller pattern. Any ideas are appreciated.

 

This is weird I was gunna say the thermostat but when you flushed it was the radiator fuild clear or did it have junk it the fluid

 

Coolant was very clean and green. However the last leg of the radiator went from clear to rusty as it passes through metal pipes to the back of the vehicle. A little rusty water in the bottom of the radiator. Appears the guy before me just put in water, no antifreeze to top it off. With no flow it picked up rust in the metal pipe. As far as being bled, I squeezed hoses and made sure radiator was topped of with a recovery tank attached. Recovery tank would fill as engine overheated.