We had a crack in our roof, about a foot long originating from the corner of the A/C Unit. We took off the A/C Unit, and found another, smaller crack. I drilled a hole at the end of each crack (to release the stress), and put a bead of RTV, smoothed with my finger, over each crack.....RTV'd the heck out of the A/C Gasket area, and reinstalled the A/C Unit.....that was 2 years ago, so far crack has stopped, no leaks. It seems that the dealer installed the A/C Unit (or factory), and forgot to round off the corners of the cuts in the roof
*Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming - "WOW, What a ride!"