How to Seal a Leaky Windshield

A leak in a windshield can lead to an annoying whistling sound caused by the wind as you drive your vehicle. It can also mean that water is able to seep into the vehicle, potentially causing interior damage or electrical problems. The seal around a windshield is meant to hold it in place and keep it watertight. But time and exposure to the elements can dry out or crack this seal, meaning it will need to be repaired or replaced. In many cases you can seal the leak yourself.

Instructions

1

Find the leak in the windshield first by visually inspecting the rubber seal around the glass. Look for tears, cracks or areas where the rubber is separated from the glass or the outer frame. You may also use a toothpick and try to wedge between the glass and the seal. If the toothpick will go in more than a quarter inch, it's likely that water can get through the space too. If you are still unable to find the leak, get inside the vehicle and have someone else spray a water hose on the windshield until you can find where water begins to trickle in.

2

Clean the seal thoroughly before beginning repairs. Remove all debris that may have built up inside the cracks or crevices in the seal. Clean away dirt and other substances from cracks, and use a toothpick to scrape out any debris caught underneath a separated seal. You will likely be able to get a considerable amount of material out from underneath the bottom edge of the windshield with the toothpick as the wind forces it under the edges.

3

Bind any loose molding around the windshield with duct tape. This is an optional step only needed if the seal around the windshield is in a condition that causes a gap where water can enter. The tape holds the seal in place so a sealing substance can be put in place.

4

Squeeze a small amount of silicone made specifically for windshield repair into the cracks or other damaged areas of the leaky windshield seal. Just put enough of the material into the leaking area to fill it and then wipe away any extra that runs out. This is a light and runny substance that will have to be handled carefully to keep it from spilling onto paint or other unintended areas.

5

Leave the silicone on the leaky windshield overnight to completely dry. The following morning it should be sealed airtight. Remove any dried silicone that got onto the glass or the rubber seal. Use a razor blade to scrape it from the glass, and peel the silicone on the rubber off by hand carefully.