Its important to note that the automobile windshield chip repair exterior trim and moldings that we can see on the outside of the glass are for looks only. The actual water seal comes from the "urethane" adhesive which is used to create the bond. Its in this urethane that the water leak is originating.
If you live where it snows, consider what ice, snow, salt, and loose gravel can do to your car. The radiator can corrode without you even knowing it, minor scratches and nicks can turn rusty, and the windshield is subjected to the extremes of interior heat and exterior cold. These factors, and others, affect your vehicle when the weather changes from winter cold to summer hot.
Check with your insurance, because it's likely your insurance will pay for some forms of windshield chip repair. They may even waive the deductible, since repairing your windshield is so much cheaper than replacing a windshield. Should you need total front window repair, you may have to pay a deductible with your insurance.
Why do you think there is windshield repair? You got it, cost. Some insurance companies want you to repair rather than replace because of cost. They save a fortune if you repair your windshield. Also, you need to check with your state as to what is legal as far as windshield repair all states have different laws regarding this issue.
The windshield is also called a windscreen. Your car's glass is very similar to that of an aircraft, or a motorcycle's wind screen. Most cars made in modern times are usually fitted with a laminated kind of glass that is very secure and safe because it doesn't shatter into sharp shards unlike ordinary glass from mirrors and bottles. These laminated glass is a kind of treated glass. It is usually made up of a dual curved sheets of glass and a layer made of plastic sandwiched in between so that it will be safer. These are glued into the car's window frame.
But the best way to fix a leak is completely removing the glass and shooting a new seal. This is the only way to truly see what is happening. If the glass is removed a technician can 100% fix the underlying issue. This option may require the purchase of a new molding. Also your auto glass company will most likely require you to purchase a new glass if the old glass breaks upon removal.