What Causes Windshield Stress Cracks Without an Impact?

Not every windshield crack begins with an obvious impact mark. Rapid temperature changes, pressure near the glass edge, vehicle body movement, or an existing flaw can place stress on the windshield and allow a crack to form.

Stress cracks often begin near an edge, where the windshield is supported by the frame and adhesive. Avoid pouring cold water on hot glass or directing extreme heat or air conditioning at one small area. Do not press on the crack or attempt to force trim back into place.

Because several conditions can look similar, a professional inspection is the best way to determine the likely cause and whether repair is possible. Cracks without a repairable impact point commonly require windshield replacement.