Well 4yrs ago i took the cowl vent off,And inside on both sides i found. Sticks & leafs clear up to the top. So i didn't want that happening anymore so i came across some window screen. Next i traced the cowl vent on to the screen. Next i cut it out,The i seen that i was going to have to cut it into two pieces.So i did.Next i shot the screens with primer 1 because it was wire screen,2 it gave it a nice contrasting color. Oh don't use red for the cowl vent,Stay with black. Well 4yrs. later NO crap at all in the cowl area,Just a little dirt was all. So it work. I used well placed zip ties to hold the screens in place plus i add 5 screws to the front of the cowl vent to better hold it into place.Here are some pic's The only thing that i had to do after this trick was just pull small leafs out from between the screen and the vent. Hope you like this and that it works for you as well as it did me. Thanks for your time. I would use the smallest zip ties you can find.