Topaz windows

Hi.

My husband and I are thinking about buying a Topaz, which seems to suit our needs well. The particular one we have in mind is a 2013 model - very clean and apparently well cared for. The main concern we have is that one of the top windows looks as if it has had some sort of sealant applied, which has then started to melt. There's no apparent damp inside the 'van, but we're worried a botched job may have been done to rectify a problem we can't see. 

Has anyone come across this type of thing before?

Any information or advice would be very welcome.

Not had that problem, but our one was a late 2007.

I would pay attention to the plastic panels, bathroom, sliding door surround and the so called cant panels running from front to back inside.

I say this as they all had to be replaced, at considerably cost to us by A/S after 3 years from new.

Just a thought, but maybe they have rectified the problems by now.
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Richard

I'm pretty sure that the roof windows will have been sealed from the factory with a butyl rubber tape - which looks very much like a white or black version of blu-tak. The factory recommendation when I re-sealed mine in around 2012 was to run a bead of clear silicone sealant around once the excess butyl rubber had been squeezed out and chopped off flush.

Does that sound like what you're seeing?

Many thanks for your quick replies. I'll check these things out really carefully. It's a minefield, isn't it?