tmaxx, I use sickaflex 21 on the sides and anywhere a standing bead is needed. Dicor is good too just make sure you use the non self leveling on areas like window seams side seams and any where a stiffer caulk is needed. then use the self leveling on flat seams like those on the roof around skylights and flanges. the worst thing to use is silicone.It does not last and it leaves a residue that other caulks wont stick to. you need to peel off all the silicone and prep the seams with a solvent like acetone to get rid of the silicone residue; clean the areas well and follow up with a dry rag. DO NOT LEAVE THE SOLVENT ON TO LONG IT WILL REMOVE PAINT! but if your careful you will do no harm. I like to dig back in under the seam a little then apply the new caulking feathering it out so you don't leave pockets for water to stand and freeze in. More than likely your leak is coming from a window or out side seam near the bottom of the cab over. eturnabond works well on flat seams but can be used about anywhere. its not pretty and its pretty much gonna be on there for a long time any where you put it and it works very well but it can be fugly if your not careful applying it. Hope this helps some
