OEM Mud guards suck. I just pulled my wheel well liners to replace them, and found 4 lbs of dirt/mud packed in behind my mud guard. The design of the liner/guad traps dirt and mositure in there. This will rot out the car quickly. Im going to be drilling some drain holes in the plastic when I put it all back together. here is a pic

You guys should take a look at yours. I only had these on for a little over a year to collect this, adn i never drove in the winter time