Jim/GA
Well-known member
What do you recommend to seal the gap?
Yes, foam backer rod. Shove it compressed into the gap.
Home Depot also sells strips of foam that are square in cross section (1"x1", 2"x2", etc.) and a few feet long. Stuff strips in there.
This area of the car won't get wet in car wash or rain, unless the whole body is under 2 feet of water.