1998 GMC Jimmy Windshield spots

1998 GMC JIMMY
14,780 MILES • 6 CYL • 4WD • AUTOMATIC
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VAR
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A couple of months ago I notice three or four dark spots that formed on the bottom of my windshield. Now they are spreading even further across the glass. They seem to be inside the glass. What is causing this? It is not a cleaning issue but possibly a tint problem due to the age of the truck? thank you.
Aug 14, 2010 at 5:37 PM
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MHPAUTOS
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Hi there,

This is moisture creeping up in in between the glass laminates, the windscreen is acutely two glass panels with a clear laminate in between, there is nothing that you can do about this problem, if you try and remove the screen to reseal any leak, you will destroy the screen.

Laminating

•After the glass is tempered and cleaned, it goes through a laminating process. In this process, two sheets of glass are bonded together with a layer of plastic (the plastic layer goes inside the two glass sheets). The lamination takes place in an autoclave, a special oven that uses both heat and pressure to form a single, strong unit that is resistant to tearing. The plastic interlayer is often tinted to act as an ultraviolet filter. When laminated glass is broken, the broken pieces of glass remain bound to the internal tear-resistant plastic layer, and the broken sheet remains transparent. Thus, visibility remains good. Unlike traditional safety glass, laminated glass can be further processed—cut, drilled, and edge-worked, as necessary. A typical laminated windshield is very thin: each glass layer is approximately .03 inch (.76 millimeter) thick, while the plastic interlayer is approximately .098 inch (2.5 millimeters) thick.

Mark (mhpautos)
Aug 15, 2010 at 3:23 AM