Chips and Cracks: When to Repair or Replace a Damaged Windshield
If your windshield gets chipped or cracked, should you repair or replace it? Drive with a chip or cracked windshield long enough, that chip or crack can become a problem.
Regardless of where you live, your windshield may take a beating. There could be pea gravel falling from uncovered construction trucks, sanitation vehicles laying down salt and sand when the weather calls for it, and the occasional chunk of unknown debris kicked up by cars passing by. I once had a pigeon fatally misjudge the 18-wheeler I was following under an overpass and fall onto my windshield. I thought my whole windshield was going to come down on me.
It’s amazing that windshields survive as long as they do.
An aside, the leading vehicle’s tire doesn’t “throw” objects toward your car, even though it sure feels that way. Instead, the vehicle just tosses it up in the air and you run into it at whatever speed you’re traveling. As I learned while working for a major tire company, when the tire touches the pavement the relative speed of the tread to the road is zero, so it can’t exert any rearward force to a rock. It didn’t make any sense when I first heard it either, but I have it on good authority that it’s accurate.
Large and Small Repairs
The good news is that smaller chips and cracks can usually be repaired by a professional for typically less than $100, according to Novus Auto Glass. A crack or chip can be safely repaired if it can be covered by a dollar bill, says Safelite Auto Glass. However, if the chip is directly in the drivers line of sight, there are more than three cracks or chips on the glass, the damage is at the edge of the windshield, or the windshield is old and covered with tiny divots, it should be replaced rather than repaired, says Safelite.
The repair process works by injecting a special resin into the chipped area. For cracks, holes may be drilled at the ends of the crack to prevent it from spreading. Windshields are made of three layers: A layer of resin or polymer is sandwiched between two layers of glass, says Popular Mechanics. Drilling to, but not through, the plastic can take an experienced hand.
If you’re unsure about any aspect of the DIY repair process, consider hiring a professional.
If your windshield can be repaired, do it immediately. A small chip can spread across the windshield if you hit a big pothole, drive on a corrugated gravel road or make an aggressive turn. If you’re on the road away from home, a repair company can typically come to you.
A reason to repair your windshield before the crack grows and the windshield must be replaced: the windshield serves as a structural part in many vehicles that contributes to the overall strength of the vehicle, according to the National Highway Traffic Administration (NHTSA). If you must replace the windshield, its strength may be compromised as the new seal may not be as strong as the factory seal. Also, even a small opening in a new or factory seal may cause water to leak into the car, says Novus. Finding and fixing the leak can be a long-term challenge as the water may enter in one location and exit at another.
Don’t, however, expect the repaired area to be as clear as the surrounding area, says Novus. You can expect to get back about 75 to 95 percent of the optical clarity.
If your windshield is severely pitted from sand, salt or other objects, replacing rather than repairing can be like getting a stronger eyeglass prescription, especially at night — it can improve visibility and make it easier to see while driving. Replacing opaque headlight covers can have a similar effect.
You may also attempt to repair the chip or crack yourself. There are many do-it-yourself repair kits available at your local auto parts store, and they typically attempt to replicate the resin injection technique of the professionals. The difference, of course, is due to the quality of the tools and materials, and training and expertise of the person administering the repair. Because these kits may not perfectly replicate a professional repair, you might want to consider using these kits on chips that are located in an inconspicuous area, like the bottom right corner of the passenger side.
Remember, a key function of the repair is to prevent the crack or chip from expanding or spreading, and also to help restore some of the structural integrity of the glass. If you’re unsure about any aspect of the DIY repair process, consider hiring a professional.
The takeaway: Repair if possible and logical. Replace if you must. And consider using a professional for best results.