Dicor self leveling sealant is what most RV's use. Camping world carries something similar if there is one near by. But you could try any place that has RV's. The top of my van has little plugs that are basically just painted over in the factory. It lets you access things like installing a roof rack. But there are about four extra on each side and I know that the paint is know to crack and cause leaks. First thing I did was put some lap sealant over them to protect them for good.
Dicor is the same stuff I used when I put my solar panel up to keep any water out where the rack meets the roof. I'm not sure about putting it on in wet weather but it would definitely work. And if you found an RV place that sells it then they will carry the eternabond tape as well that you could seal it up with.
Dicor is the same stuff I used when I put my solar panel up to keep any water out where the rack meets the roof. I'm not sure about putting it on in wet weather but it would definitely work. And if you found an RV place that sells it then they will carry the eternabond tape as well that you could seal it up with.