Electric water pump BBL

Actually a properly sized electric fan will do more than an engine driven fan, especially at idle. Many new cars only have electric fans. That's not the problem. Sealing the radiator to the core support is good advise but if he's installed a pusher fan on the engine side of the radiator he's just pushing hot under hood air through the radiator.

A pusher fan should be mounted in front of the radiator. Puller fans actually work better, mounted on the engine side of course as they don't block the front of the radiator.

As far as circulating the water too fast, again that's not going to happen at idle and isn't a concern here.

What I'm wondering is what size the radiator is, how many cores, and do you have a thermostat in it and if you do what temp it is? Do you run antifreeze, water, or additives in the coolant?