I have a 2007 Hyundai Tuscan which has just began to leak near the sunvisor area on drivers side. I took it to my mechanic who suggests it is coming from the roof racks. When it is raining you can see the water dripping I side. We have tried a silicon from Bunnings but it hasn't worked. Has anyone else had this issue? Thank you

 

I'm not sure if the roof rack anchor is mounted from the outside or from the inside.
If it is from the outside, all you might need to do is loosen the mounting screws , place some sealer under the mounting and retighten the screws. I wonder if this is all that was required your mechanic probably would have done that. Is it possible for you post a picture of the ones on your vehicle?