I too recommend the Eternabond tape! I used the 4" wide Eternabond to reseal all the large openings such as skylights, vents, etc., and the Dicor 502LSW self-leveling sealant on the small openings such as vent pipes, TV antenna, etc. You can put this on over any existing sealant, just clean it good with alcohol or acetone.
One caution! NEVER use anything that has a silicone base!
Good luck, happy trails, and God bless!
Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD