I have an 05 F-150 Supercrew. Bought it in 08 still in warranty--no issues, but as the miles wore on, a niggling rattle began to wear on my nerves. It felt and sounded like it was in the cowl area--both the rubber ends of the cowl are long gone. I've used body putty, silicone, even pennies to stop anything I could find that was rattling. It was maddening! It started out as only rattling when there was a strong cross wind, then as the miles wore on, it took less and less cross wind. The hood on this truck has always vibrated and shook but I never could isolate the rattle. Dealer just shook his head. I couldn't replicate it even with a leaf blower!
Then......last week with 4-6 inches of sleet and snow piled up on the truck, I went for a drive. When I hit the brakes a huge chunk of ice slides off the roof of the truck, crashes down on the hood and shears about 1/3 of my oem bug shield off. Made me sick! I waited until the weather got better and took the snaggle-tooth remainder off and went shopping for a new one. Didn't find one in stock locally and decided to go without for a while. Guess what?
NO MORE RATTLE! I can't believe how much quieter the whole truck is! Hood is rock still now at speed and the March cross-wind is howling.....still no rattle! Funny thing is I checked the bug shield several times, but it was tight as a tick. The bug shield was causing the rattle by changing the air flow over the front of the truck.