Well, here is something that I had to learn the hard way. We developed a leak in our 5er. It leaked down the back wall and swelled the window sill on our bay window. I called the dealer and he said when is the last time you checked the seals on your caps? I told him that I had never checked them since I bought it. He said they recommend that they be checked a minimum of once a year and that twice is better. I don't ever recall them telling me this.
I climbed up on the roof and inspected the seal between the rubber roof and the endcaps. Sure enough there were cracks in the seal. I purchased some caulk specifically for this. It is more expensive that standard caulk at $7.30/ tube. It is self leveling caulk and has a shelf life of one year. So no need to buy more tubes than needed like I did. I bought 3 to have them on hand. Had to take two back as 1/2 a tube did both the front and back caps.
Hope this helps anyone that hasn't heard of inspecting their cap seals. Might save you some headache.
2000 35' Carri Lite fifth wheel with triple slideouts. Rear living room with a 20' awning.
99.5 Ford PSD crewcab Dually, with a Western Diesel tow chip. Set of 3 gauges, Pyro, boost, and tranny temp. Banks brake with smartlock and a Banks Monster ex