I'm sure some (a lot) of you have experienced this, but I did a search on here and came up empty.
Now, my search of the internet for a solution to the squeaky seatbelt found endless solutions involving destruction!!
The seatbelt rubs on one of the ribs of the cover trim on the B pillar.
The generally accepted solution on you tube and other sources is to take the trim off and cut away the offending rib. The first rib down from the top opening.
Now, after 35 years of working on cars, that solution screamed out "Bandaid" to me. If you have to cut something to fix something, 90% of the time you are missing the point.
So, after viewing half a dozen Youtube videos all giving the same solution, I noticed on one that there was a bead of "stuff" on the bottom of this offending rib.
Ah Ha!! I see it. This bead of "stuff" would appear to be some sort of wax type substance (factory applied? Dunno). I can do that...
After removing my cover trim, should have taken pics of this for you, but too late now, I took it to my work bench and stood it upside down, with the ribs facing out. Offending rib will now be first up from the bottom.
Off to the kitchen to fetch a candle. Light the candle, drip a thick bead of wax onto the offending rib, which will in essence be the underside of the rib. Fill it up till the wax starts to build over the edge of the rib, run all the way across the rib.
That's it. Job done, reassemble, squeak gone. No butchery.
If you have enough wax over the edge of the rib, by the time you are back down to the plastic, there will be enough wax on the belt that it will keep itself lubricated. At least it should.