Why Can't You Feel the Crack on the Inside or Outside of the Front Windshield?
2 Answers
The reason you can't feel the crack on the inside or outside of the front windshield is that car glass consists of two layers, and the crack is likely on the inner layer. The inability to feel it from the inside is probably due to the presence of a sun film. Introduction to Windshields: Automotive windshields are generally designed as a single large curved piece with certain curvatures on all sides. This curved glass, whether in terms of the manufacturing process or the fitting during assembly, is a product that requires high technical standards, as it involves numerous factors such as vehicle model, strength, heat insulation, and installation. Functions of Windshields: The primary function of a windshield is to provide a survival space for passengers. Upon impact and shattering, the glass breaks into small pieces with blunt edges, minimizing harm to occupants. Currently, most front windshields are made of laminated tempered glass or zoned tempered glass, capable of withstanding significant impact forces.
The front windshield was cracked but couldn't be felt when touched from either inside or outside. I've encountered this situation before. The reason might be that the damage occurred within the interlayer. Windshields aren't single-paned; they consist of three layers: the outermost layer is glass, followed by a plastic film called PVB in the middle, and then another layer of glass on the inside. The PVB film acts like glue, bonding the two glass layers together, which not only cushions impacts but also prevents injuries from flying shards upon collision. If the crack only occurs within the interlayer or is a very fine surface scratch, it will feel smooth to the touch. Common causes include small stones or branches hitting the glass on highways, damaging only the surface without penetrating the interlayer, or temperature changes causing uneven internal stress in the glass, leading to hidden cracks. If left untreated, small cracks can gradually expand into larger ones due to vibrations, affecting driving visibility and safety. I recommend driving to a professional auto repair shop as soon as possible for inspection and treatment with repair agents or a full replacement. When parking, avoid areas near trees or construction sites to reduce the risk of glass damage. Regular car washes can also help detect damage early.
