No, you should not wash your car, especially with a pressure washer, if you have a cracked windshield. The primary risk is that high-pressure water can force moisture into the crack, compromising the adhesive layer (the urethane seal) that bonds the glass to the car's frame. This can lead to leaks, wind noise, and, most critically, reduce the windshield's structural integrity. In a collision, the windshield provides up to 60% of the passenger cabin's strength in a frontal impact and up to 75% in a rollover. Washing a cracked windshield can turn a repairable chip into a full replacement necessity.
The main concern is water and pressure. A simple hand wash with a bucket and gentle stream of water is less risky but still not advisable. The soap and water can seep into the laminate (the plastic layer between two sheets of glass), creating a hazy, opaque area that severely obstructs your view. Furthermore, temperature changes are a major factor; if water gets into the crack and freezes, it will expand and can cause the crack to spread rapidly across the entire windshield.
The safest course of action is to get the damage assessed by a professional auto glass technician immediately. Small chips can often be repaired quickly and inexpensively, preventing the need for a full replacement. Driving with a compromised windshield is a safety hazard, and introducing water through washing only exacerbates the problem. Your priority should be repairing the crack, not washing the car.
