My car is a 2008 Grand Marquis with Gold and Chrome trim, and a landeau vinyl roof.
About 5 years ago, the vinyl started to split. I took it to a friend's place to have it sealed and painted, thinking that would cost less than having it replaced. Even at that time, I figured that replacement would cost more than the car was worth. When he refused to paint vinyl, I decided to get some Flex Seal, and have a go at it myself.
I bought a quart, and brushed it on. My brother exclaimed, "You put it on with a brush? There's no denying that you're your Father's son!" LOL, my Dad would have said, "A man riding by on a fast horse 50 feet away, will never see the difference."
IMO, it came out pretty well. Yes there were brush marks, but at least the splits were water proofed. If water gets underneath the vinyl, and freezes during the winter, it will cause the vinyl to pull away and get really ratty looking.
It held up for three years. The next time I bought some spray cans. The spray didn't come out as well as I had hoped, but it was sealed up again. It also didn't hold up as well, and needed to be reapplied a year and a half later.
OMG, I hadn't realized how terrible it had started to look.
So here's a before and after picture. I expect the Flex Seal to hold up for another three years. It'll remain soft and flexible. Although I haven't needed it to seal any leaks, anywhere, I wouldn't hesitate to recommend it. It is easy to apply, is very sticky, dries quickly, and is relatively long lasting.