Has anyone had experience with corrosion forming in the channels on the roof ?

I have a 2001 A6. I had one small spot show up last year. Now they have multiplied all along the channels.

I wondered if Audi's corrosion warranty covers this?

Is my only course of action to have the entire roof treated and repainted?

I would appreciate any imput

 

I've had 3 customer cars come through the shop with that same problem two were avants and one was a sedan. One avant came from CA, the other Avant from AZ, and one lived it's entire life in TX.

Audi's corrosion warranty only covers perforation from what I was told.

If you have it fixed make sure that the rust is blasted out and the seam sealer is removed and replaced. I think what caused it was a crappy seam seal job on hte roof panel and side panel joints at the factory.