He stated engine was fine after a T stat change last year, and did not start getting real hot until "right after" he replaced the water pump. I am betting they sold him an A/C type 6 bladed pump. Y'all are shooting down the wrong snake hole. If it was a plugged radiator issue it would have gotten hot before and after the water pump change. It's getting hot only after the pump change. That is the only thing coolent related he changed right before this started to happen. Car is non A/C with the larger slower turning pulley, and probably has the wrong 6 bladed A/C pump on it. It's not flowing enough coolant for the impeller speed.
