This is the honey comb pattern of the grill cover. As you can see it is about 1/2" deep. Which makes for a big array of whistles.
I picked up a screen door protector from Home Depot. These are used to keep dogs from jumping through the screen. This one looked open enough to not effect airflow over the radiator. All I was really looking for is to create turbulence to eliminate the whistle.
Here is the protector over the honey comb grill. The Whistle now only shows up at a very specific speed (depending on the wind) and at 1/10 its previous level. Before this fix it would whistle at any speed between 50 and 70 mph and it was louder than normal speaking level.