Dicor lap sealant

Yes you can use that.  Or you can put some eternabond tape around it for a quick easy fix.  I did that on a fan on my old trailer that was actually leaking.  I sold the trailer 4 years after that repair and it still did not leak.  I honestly do not know what is a better solution.  Dicor certainly works very well but it does need to be replaced from time to time.  I'm sure eternabond does as well but it certainly is easy to apply.  I always keep a roll in my trailer tool bag in case I need to make an emergency repair while out traveling. 

The dicor on my old trailer was very thin and I actually just used eternabond over it.  Like I said it was still  completely sealed after 4 years.  I would not hesitate to use it again.  If I ever have to use it again I would remove the old Dicor but heating it up with a heat gun or hair dryer and use a putty knife to remove it.  I think both dicor and eternabond are good products but I believe eternabond will last longer and in my experience is less likely to crack and dry up over time.  Dicor is very good but seems to require more frequent maintenance.  I think eternabond works very well on fiberglass and aluminum roofs.  The arguement above is for membrane roofs which I'm sure would be much harder to remove eternabond from if needed.  Everybody has an opinion on what works best.  I've never replaced dicor with more dicor so I can only comment on my good experience with eternabond.