Hi
I know I post alot 
My sun visor won’t stay up. Is there any way to tighten this? It’s fine except having to lean forward to see if the light has turned green yet.
Get one of those great big paper clips, they are like a spring-loaded clamp used to bind a big stack of papers. Clamp that on the base of the visor to provide more friction. Works for me…
Sometimes you can just force the rod into the visor (with you hand) and thata all it takes to keep it up
Is there a sprocket inside or something else that’s come loose?
There were some posts a while back concerning the same problem with the Nissan Murano. Several solutions were given. One idea would be to go to an upholstery and trim shop. These shops deal with sun visors and may be able to remove the upholstery, fix the mechanism and reassemble without asking for an arm and a leg.
You could try obtaining a replacement sun visor (one that still works) at a junk yard. There is no tension adjustment on a modern visor that I’m aware of. I think the problem is age and wear.
How about some velcro? Glue a piece to the head liner and another piece to the back of the visor. That should keep the visor up.
The upholstery shop is the best suggestion. Collagen injections won’t help.