Anyone use one or even heard of one? Someone here some time ago put one on and it makes sense (to me anyway.)

The radiator does it's job once the engine's thermostat opens up and allows coolant to flow through the radiator. Blocking the grill keeps air from flowing through, but why not block it at the engine and allow the radiator to do it's job?

I'm sure I'm not the first one to think of this. Tell us all what you think.