Seitz Window Crack

[bonfireboy]

I've got a 1996 van (had from new) - a small crack has appeared in the top curve of the outside of one of the top hinged windows.
Price to replace seems to be around £250 plus - it is a big window.
Any ideas what the crack can be sealed with or if it is likely to suddenly go right across the window even if sealed?

 

[Brum1]

I believe that if you drill a very small hole at the end of a crack, it will not get longer.
You could then run clear sealer over the crack and into the drilling.

Hope this helps
Brum