There is a small slender stip of rubber ~2-3mm in the the water channel / gutter on my car that seems pushed in on both sides for most of it's length except for the first and last 6" or so. What does it do? Am I getting water in where I shouldn't be or it it just a rubber gasket between the roof and top frame? Can I simply pluck it out or does it need replacing? How difficult? Part #'s?