Hi dkelkins and
First it is always helpful to have additional technical info on you particular RV. I see from your Profile that you have a 33' Coachmen but that covers a lot of territory. Motorhome? 5th Wheel? Travel Trailer? What is the roof covering made of? Probably is a rubber roof, but metal and fiberglas have been used. Is there any chance you can post a picture here for us?
Since it is leaking, you need to repair it, which means applying a patch over any damaged areas. This could be a tear or hole on the roof material itself or a separation at a seam or edge along a vent or skylight. Have you inspected the roof and found the source of the leak? Keep in mind that where it leaks inside could be several feet from the leak source outside.
Most folks recommend a patching tape called Eternabond. There is a similar tape under the Dicor brand. Your local RV supply store should have one or both of these. I would also pick up a tube of Dicor sealing caulk (again, for rubber roofs). You can use it wherever the tape might be hard to apply or if you have just a small pinhole to fill.
DO NOT use normal "home improvement" products like BlackJack or mobile home roof sealers. They are not designed for RV roofs and will cause you more problems later when you try to remove them.
I would consider recoating the same as sealing, though you might say that applying sealant caulk along the seams and edges is "sealing" the roof. Normally there is no need to apply a coating over the entire roof unless the whole roof surface is deteriorated.