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How to Find a Windshield Leak

windshield leak
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Ever noticed water or a whistling sound coming through your windshield? There could be several reasons for this, but first you have to pinpoint the problem. Your auto glass is held in place by urethane, which is an adhesive that’s applied similar to caulk. Urethane, coupled with a moulding, keeps water, air and/or other debris from sneaking into your vehicle. This is the integral component that seals your windshield to the frame of your car. So if water, air or debris is coming in take these five steps to pinpoint the leak.

1. Find the Source of the Leak

Locating the source of the leak is harder than it sounds, according to many experts. But you want to find the source to avoid damage to the vehicle, such as rust, mildew and even electrical problems. Remember that the leak doesn’t necessarily appear close to the source. Water can enter the vehicle and travel a ways before reaching the inside. Also keep in mind that even if there is only wind noise, and no sign of water, chances are that the leak is still letting in both.

Pay attention to when the leak occurs. Is it every day or just after it rains? Does it happen in hard rain only or light rain as well? Does it happen when the car is moving and parked or just one or the other? Don’t just look for water but water stains as well, which may have happened without you seeing them. Have a friend sit in the car while you apply water to the windshield from the outside to see if he can find where the water is coming in, if it is coming from the windshield.

2. Determine the Cause with a Windshield Leak Test

The windshield frame interface is the most common place to have a water leak. If your leak started soon after you had your windshield replaced that is likely the culprit. When the windshield

windshield leak

comes out, the technician seals the new windshield in place with black caulking. If the right amount of urethane is used the windshield may not seal properly. Since the adhesive takes some time to dry, the vehicle should not be driven until the time the technician tells you. Your auto glass tech should have given you the minimum drive away time: this varies depending on the sealant used and other factors. Contact your auto glass company if you believe this is the issue so they can rectify the situation.

It is very important to find a reputable auto glass company when you need a windshield replacement to avoid leaks in the first place. According to auto glass expert Bob Beranek, the following may also be reasons your windshield is leaking:

  • The technician used ungloved hands to set the windshield and the oils from their hands contaminated the top driver side corner of the windshield and kept the urethane from adhering to the glass.
  • It can be difficult to get a smooth clean strip back to the top corners, due to their sharpness. Flaps in the original adhesive bead can occur while stripping the existing bead thus causing a leak between the two pieces of urethane.
  • Or, it could be an indication that the vacuum cups and setting tools were not used: It could be because the technicians were not trained in their proper use.

Beranek also says the auto glass company should not be performing an installation while it is snowing or raining unless the vehicle is under cover as urethane doesn’t stick to a wet surface. If your installation occurred in this environment this could be the cause of your leak.

The next time you need your windshield replaced be sure to check to find a reputable auto glass company and make sure the above doesn’t happen.

3. Check the Sunroof for Leaks

Sunroofs are a common area for leaks as well. If the seal around the sunroof becomes damaged, water can enter, especially when driving through rain. Check with your vehicle manufacturer for tips on how to find the source of the leak.

Leaks around a sunroof are not entirely uncommon. A article in September 2016, reported a safety recall from Ford for approximately 900 2014 Ford Transit Connect vehicles to reinstall panoramic roofs, according to the automaker.

Ford says the cause of the recall is due to “ … an improper bond [which] may exist between the panoramic roof and the vehicle body, resulting in wind noise, water leaks and, in some cases, separation from the vehicle. If the entire panoramic roof separates from the vehicle while driving, it can increase the risk of crash or injury.”

Similar cases include a class action filed against Chrysler for a sunroof leak and BMW as well as others.

4. Is the Door Seal to Blame?

If the windshield or sunroof isn’t the culprit, the leak could be coming from the door seal. While you should never attempt to replace your windshield on your own, you could fix a leak in a door seal fairly easily. Look for replacement seals with a self-adhesive strip at your local auto parts store, or take the vehicle to your local auto body shop to have it done professionally.

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If you have gone through all of the steps above and still can’t find the source of the water or air leak in your car, contact an auto glass company in your area who can help by using’s search tool. Have you had success finding and fixing a leak in your windshield, sunroof or door seal? Let us know in the comments below.

Please note, this article may contain links to Amazon products. As an Amazon Associate, earns from qualifying purchases.



Tara Taffera

Tara Taffera was the editorial director for USGlass magazine, AGRR Magazine , and Window Film Magazine. Her skills and more than 20 years of experience have helped her earn numerous journalism awards, including coveted Jesse Neal Awards. Tara enjoys spending time with her family and staying active with her husband by competing in races together, including triathlons. She also spends time volunteering in her community and with her church. Find out more about Tara on Linkedin.

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