The fan in our 2013 Leaf suddenly started making a racket. It turned out to be a mouse in the fan drum. At first it looked like there was no way for a mouse to get in through the grill under the windshield, but I ran my hand up under the left passenger side of the windshield and found an opening several inches wide. The same spot on the driver's side was filled with foam. I stuffed some foam in the gap and am hoping for no more problems.