Originally Posted by ecrase2500

Thanks for the feedback, folks. Aussietrail, yours was one of the posts I had read while I was fiddling around under the speaker grille, and I tried foam in a couple of different places. One was around the part of the speaker grille that has the vent for the duct. I wrapped it with thicker adhesive foam to make it seal better than the flimsy foam already there. I thought this might help the hissing too, but it didn't. I also tried a piece of foam under the plastic duct itself, where it seemed to sit. I had no luck in silencing the noise, but I'm glad I ruled that out - I might not have thought of it otherwise.

In my case it's less of a rattle per se than the sound of two pieces of plastic rubbing together hard and releasing suddenly with a "flick". I should have described it better. Sometimes I wonder if it's the windshield shifting about in its seal.

I guess I'll get used to the hissing noise, if that's standard fare in X-Trails. I'm less obsessive about stuff that bugs me if there's no fixing to be done. But that wouldn't qualify me as a satisfied customer...