I have a '99 A6 Avant with about 70M on the clock. Bought it about 6 months ago, and all has been great. The rearview mirror and the two side mirrors are (or were) a strong yellow, which I thought was a tinting film.

Last week, I noticed what appeared to be an air bubble at the top of the rearview (interior) mirror. no problem, I thought, the film is coming loose, and I can just peel it off. Later that day, I noticed that it was growing, and as I was watching it, it started bubbling from the bottom! Within a few minutes, it was dripping (onto my pants...great!) and had emptied by the end of the day.

Evidently the yellow is some kind of fluid for dimming, but now that it's gone, the mirror looks smudged (presumably residue on the inside)

What's the best remedy? Replace the assembly? REplace the glass? With or without a fluid-based mirror?

 

I've never heard of that happening. I just have the traditional mirror with the flip switch for dimming. I'd say find out how much it is to replace it and go from there.

 

This is actually VERY common on the auto dimming ("anti-dazzle") mirrors (mine are brown).

So to give you an idea of what you can do, check what this guy did (mostly just look at the pictures to see how things come apart): http://uk-mkivs.net/forums/t/204182.aspx

Probably the easiest is to find used ones that are still good. I'm still trying to decide what i want to do, this came up as an option but i never pursued them: http://www.auto-glass.com/catalog/audi.htm

One of the best places for used Audi parts is: http://www.shokan.com/