Rear and Side Tempered Glass Spots (Quench Marks) – GM Passenger Cars and Trucks

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Bulletin No.: PI0754D
Date: Nov-2020
Subject: Rear and Side Tempered Glass Spots (Quench Marks)
Models: 2021 and Prior GM Passenger Cars and Trucks
Attention: This PI also applies to any of the above models that may be Export from North America vehicles.
This PI has been revised to add the 2020-2021 Model Years. Please discard PI0754C.
Condition/Concern
Some customers may comment on spots showing on the rear and side windows when the vehicle is in the sunlight. When wearing polarized glasses/sunglasses,
these spots may be more magnified.
The spots are due to the manufacturing process and are “quench marks” in the glass. Quench marks are an unintentional side effect of the tempering process.
Recommendation/Instructions
Technicians should explain to the customer that this is a normal condition and part of the manufacturing process for tempered glass. Do not replace the window(s) for
this condition.
Note: This will not be seen on front windshields or laminated side glass.
GM bulletins are intended for use by professional technicians, NOT a “do-it-yourselfer”. They are written to inform these technicians of conditions that may occur on
some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety
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instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle
will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
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