[aerohead]

I'd pop the hood open, and look to see that the adhesive bonding between the pressed-steel superstructure underneath the hood hasn't separated from it's metal outer skin. ( I have this condition on my truck )
The engineers try to create a small high-pressure separation bubble at the cowl area, in order to provide passive airflow into the cabin ventilation/ heating/ air conditioning system ductwork.
If the skin is properly 'glued down' you'll never know the turbulent bubble is out there.