I have the dual pane windows in my UL, and since I bought it the rear left window has had issues. I guess the gas inside started escaping so it left some really strange designs in the bottom of the window. Now my front window had a issue with it too with the gas, and now I see it starting to spread. It almost looks like a white vein in the window and like its partially fogged up. Its really hard to explain, I'll try to post some pics tomorrow. For the guys who know what I may be referring to, is there any way to seal this or prevent it from spreading? I read a thread a while back showing how expensive these windows are, I'd prefer not to have to replace them, but my rear looks rather crappy.

 

I have not heard that they have gas (between panes), but that they are laminated two-layer. Do you have a source for this information?
Thanks.

I think the problem described is delamination.

 

I have the same problem in the drivers-side rear glass. It looks like it's spider-webbed in the lamination between the two layers, at the bottom of the glass.. I've consulted two businesses that deal in tint on high-end cars, plus had the parts manager at my local dealer come out to see it, and all agree it's in the glass and can't be repaired but to replace it. I ordered new glass through Lexus of south Atlanta, best price I could find, and have yet to install it. I think this is your only option unless you can find used. Be cautioned that there are thickness differences between the non-and-UL models, so you'll need to use a micrometer on the old glass to make sure you get the right part. Good luck!

 

This is exactly what it is. Delamination is basically the breakdown of the adhesive (or laminate) that bonds the two pieces of glass together. It is mostly a problem on highline vehicles because, well, 'regular' vehicles usually don't bond two pieces of glass together to aid in cabin silence...you'll see it a lot on older S-Class and 7 Series vehicles. I have not seen a fix for this; once it starts, you either live with it (a pain because it looks weird and makes tint film cloudy), or replace the glass (which isn't cheap, because, well, two pieces of bonded glass for a luxury vehicle)...hope this info helps.