I had a window leak in my other camper (2001 Shamrock). I took the window out, cleaned out the old butyl tape, installed new butyl tape and remounted the window. After the tape stopped oosing out I applied a good grade of silicone caulking around the edge (outside)
2013 Prime Time 230 FBS
Days camped in 2013: April to November
Days camped in 2014...about 40
Days camped in 2015...more than 2014!!