1984-1986 CAPRI 1984-1987 LYNX 1984-1992 MARK VII 1984-1994 COUGAR, GRAND MARQUIS, TOPAZ, TOWN CAR 1986-1994 SABLE 1988-1989 TRACER 1988-1994 CONTINENTAL 1991-1994 CAPRI, TRACER 1993-1994 MARK VIII
1984-1990 BRONCO II 1984-1994 ECONOLINE, F-150-350 SERIES, RANGER 1986-1994 AEROSTAR 1991-1994 EXPLORER 1993-1994 VILLAGER
Vehicles may exhibit iridescent spots or "mottling" in tempered glass under some lighting conditions. This condition is caused by the tempering process.
Explain to customers that "iridescence" or "mottling" of tempered glass is a normal condition and that glass replacement is neither warranted nor necessarily effective in resolving the condition.
DESCRIPTION OF CONDITION
The somewhat iridescent grayish or blueish and fairly geometric spots detected in side and rear window tempered glass are characteristic of tempered glass.
The mottled appearance is noted only under certain conditions of lighting. The occurrence of mottling does not affect glass quality or durability and cannot be reduced by scouring the glass surface.
The boldness of the mottled pattern in a given glass may vary, depending upon lighting conditions, but may appear intensified if viewed through polarized sunglasses.
CAUSES OF CONDITION
Atmospheric dust and other angular reflections can cause changes in the polarized properties of natural light. This polarization, combined with the light polarizing properties imparted to tempered glass by the forces of tension and compression (during the tempering process), cause the iridescent or mottled appearance.
These are the same forces of compression and tension which make tempered glass so remarkably strong. Windshields, which are annealed rather than tempered, do not exhibit iridescence.