Well I just got back from vacation.... using our 2019 Sorento...yes we are a Kia family for sure. Have to say the Sorento EX is a nice SUV. Had that thing packed for a two week trip to NJ shore with bike rack holding 3 bikes...drove great. Solid and Stable at highway speeds fully loaded.
Now to business.... I tried exactly what Turbocommuter said above regarding pushing up around the edge of the headliner all around the sunroof glass. I used the palm of my hand and gave a solid push all the way around. In two spots I felt and heard a "click".... you could feel the Velcro strips connecting better. Drove the car and now it is quite...not a single creek from up top. Had the car at two dealerships and neither could fix issue. They tighten all the bolts on the rails... grease the rails and told me they could not fix issue without ripping apart sunroof. I called them today and told them the fix for their records.
All that said, for all those that are hearing a plastic type crinkle sound from above your head.... not a rattle of metal.... and if you open sun shade or glass or tilt glass and non of that makes the sound go away....then most likely your fix is a 30 second push of the headliner where it meets the opening (all around) listening and feeling for a "click" sound is all all you need to do.
I am anal when it comes to noises from a new car and this noise is gone now.
Who is disappointed we didn't get the suede headliner?
