trying to find something to preserve the top on a 2002 lincoln exececutive hard top conv.

I assume you're dealing with a vinyl roof. If so, POR15.com has a great vinyl protector that I have used on my 2006 Grand Marquis vinyl roof since new in 2006. The car has always been outdoors and I use the protectant (called POR-15 Boss Gloss) once a year. The roof has looked good for 12 years here in NJ. I wash and scrub the textured vinyl roof, let dry and apply Boss Gloss with a piece of terry cloth towel. Boss Gloss leaves a subtle gloss that lasts a year for me. A container lasts me for several applications, 3 or more years. Here is the website: www.por15.com/Boss-Gloss_p_122.html (notice the two underlined characters) $11.75 per container, plus shipping. On the down side, it's currently out of stock when I checked today, 6/25/2018. There's a customer svc phone number that might help to find when it might be back in stock. Hope this helps!