[tucsonjwt]

Is the water pump actually pumping coolant? Do you see evidence of a water leak (rusty water trail) at the weep hole on the bottom of the water pump?

If you need a fan clutch, I would stick with AC/Delco factory part. I have not had good luck with flex fans. From the symptoms you describe, it sounds more like a bad fan clutch to me. When the engine is overheating and you pop the hood to check the engine, do you see the fan moving?

If ll else fails, a rare but possible coolant passage obstruction in the engine block could be the cause. A power flush might help that. You would have a shop with a power flush machine do that, along with a cleaning agent.