Sealing around the A/C

[Chuck]

I've been prepping for re-caulking up on the roof...vents and the antenna are the main focus, but I thought I'd check out the a/c while I was up there. It seems like the metal roof just "ends" at the ac; no flange or anything around there. there is a spongy gasket that makes a tight seal around the opening in the roof, but I'm wondering if this is "leak proof"? there are a couple of small remnants of caulking around, but it doesn't really look like caulk would stick to this material. its not like a metal-to-metal joint....what should I do with this? just leave it? caulk it?

[Airstreamer67]

I installed a new Coleman 13,500 BTU unit on my Overlander. It's been a couple of years now, but I don't remember using anything on the gasket that came with the unit. I haven't experienced any leaks so far.