3 Proved Ways How to Fix a Leaky Windshield. Comprehensive Guide.

Written by Oliver

August 15, 2022

Have you ever noticed water pooling on the floor of your car after a rainstorm or run through the car wash? If so, you are not alone. Unfortunately, windshield leaks are a common problem, and they can cause serious damage to your car’s interior.

Windshields are designed to keep water out, but sometimes they fail to do their job. In most cases, defective glass adhesive is the culprit. If the seal around the glass is not intact, water can seep through.

Person is driving a vehicle in the rainy weather, windshield is wet

Reasons For a Leaking Windshield

Most people think that a leaking windshield is caused by a crack or chip in the glass, but this is not always the case. In fact, there are several common reasons why windshields leak, and often, the problem can be repaired without needing to replace the entire windshield.

I’m breaking down the most significant reasons below:

Improper windshield installation


If the windshield isn’t properly sealed, it can allow water to seep in and cause damage. During the windshield installation, the auto glass technician applies special urethane adhesive on the windshield metal frame (pinch-weld). If, before that, the surface wasn’t correctly prepared, the adhesive may not properly stick to the surface, causing breaks between windshield and frame.

In addition, if the windshield was installed in bad weather, there is the possibility that the seal would be compromised. That is the actual reason why professional auto glass technicians refuse to take a windshield replacement order during rainy or snowy weather.

Rust on the metal frame under the windshield


Another common cause of a leaking windshield is rust. Rust can form on the metal frame of the windshield, causing it to expand and contract. This can cause the sealant to break down, allowing water to seep in. This is especially actual for older vehicles.

Aging and deterioration of urethane adhesive


Over time, the urethane adhesive that seals the windshield in place can begin to break down, leading to water leaks. As the adhesive deteriorates, it loses its ability to form a tight seal around the windshield’s edges. Often that happens when the poor quality adhesive was used during the windshield installation.

In addition, the deterioration of the adhesive can also cause the windshield to become loose, increasing the risk of an accident.

Deep cracks and chips on a windshield


Cracks and chips on your windshield are more than just unsightly imperfections – they can also lead to severe problems. If a crack or chip is deep enough to break through the windshield’s middle layer, water may be able to seep through and cause leaks. (Read more about windshield structure here)

Warning Signs of Leaky Windshield

A leaking windshield is an actual irritation for car drivers. Fortunately, if you identify some warning signs, you will be able to fix a windshield leak before it’s getting too late. Water dripping through the windshield may be almost microscopic, but some warning signs indicate that windshields are ineffectual:

  • Wet upholstery or carpets;

  • The odor of the moisture;

  • Mildew or mold inside the car; 

  • Fogged up windows;

  • Rusty spots on the dashboard;

  • Condensation on the inside of the windshield on a cold day.

If you ignore warning signs of a windshield leaking, you may have to face electronic failures in your car. If the windshield leak reaches the ADAS sensors, they can also fail. As a result, it is crucial to take care of any potential problems with your windshield before they become serious.

How to Actually Fix a Windshield Leak?

While several options are available to repair a leaking windshield, it’s important to know what NOT to do when facing this problem. Do NOT use sealants or silicone on your car if they’re not designed for vehicle windshields. They may contract in the cold and expand in hot, making the problem much worse instead of better!

Once you identify the source of the leak, it will be much easier to manage the problem. Depending on the type of leak, you can use the following methods to fix the problem:

Use flowable silicone sealant to fix little holes in a windshield glue

This windshield leak repair is viable when you have a rusted windshield frame, urethane glue has deteriorated, or it wasn’t appropriately applied during windshield installation. This type of repair is also reasonably cheap. You can buy this type of silicone anywhere between 5$ and 20$ per pack on Amazon. Usually, 1 pack is more than enough.

How to use flowable silicone sealant to fix leaky windshield:


  1. Carefully remove (pull up) plastic trims or/and rubber seal around the windshield;
  2. Allocate leak source by pouring water on the windshield (shower test);
  3. Take on rubber or nitrile gloves (silicone may be harmful to your skin)
  4. Clean gap between windshield and frame with rubbing alcohol;
  5. Use paper tape to cover the windshield and car’s paint on the roof from sealant;
  6. Fill up flowable silicone sealant into the gap above the leak source and level it out across the gap length with a finger;
  7. Remove excessive sealant with cloth or paper towel;
  8. Let sealant seep into the leak source and wait until it dries (it takes around an hour);
  9. Remove paper tape from windshield and car’s roof and check sealed place on leaks with water.
  10. You are ready to go!

If your windshield has deep stone chip, use a windshield repair kit

The DIY windshield repair kit is available at any auto shop or online. They cost around 10$-15$. The kit usually contains a plastic pedestal, plastic syringe, curing film, razor blade, and resin that is used to fill in the crack or chip. After the resin has been applied, it needs to be cured in sunlight or hardened using ultraviolet light.

Once the resin has been cured, it will effectively seal the chip, preventing water from seeping into the car. In most cases, the repairs are virtually invisible. However, if the damage is extensive, it may be necessary to replace the windshield.

How to use a DIY windshield repair kit to fix stone chip:


  1. Clean glass around chip with glass cleaner and let it dry;
  2. Mount sealing tape around the chip. Tap on seal should be on top;
  3. Stick a plastic pedestal over the sealing tape. They must be aligned together;
  4. Fill the stone chip up through the hole in the pedestal with crack resin;
  5. Push the plunger on the plastic syringe in, and insert it into the pedestal hole;
  6. Make a vacuum by lifting the plunger up until it is locked on top of the syringe. Leave it for 10 minutes;
  7. Pull up the syringe from the pedestal to remove the vacuum from the chip;
  8. Insert syringe back into the pedestal hole and gently push the plunger down until it is locked to apply pressure on the resin. Leave it for 20 minutes;
  9. Remove syringe, pedestal, and seal from the windshield;
  10. Fill a little bit of resin on top of the chip and apply a curing film. Leave it for another 20 minutes.
  11. Remove the curing film and scrap excessive hardened resin with a razor blade. Don’t worry, the blade won’t damage the glass;
  12. Wipe the glass around the chip, and you’re ready to go!

What to do in case your windshield leaks through the deep crack:

If the crack is deep enough, it can weaken the windshield’s structure and cause it to break in the event of an car accident.

DIY repair kits are not designed to repair deep cracks, so they will not provide a long-term solution. You’ll likely be left with the situation where water is still seeping through the crack after windshield leak repair.

The best option is to contact a professional auto glass technician to fix the crack, if possible. If the crack is too severe, the entire windshield must be replaced. Either way, taking care of a cracked windshield as soon as possible is essential to ensure your safety on the road.

US Auto Glass Has You Covered!

US Autoglass logo

If you decide to replace your windshield, you can get a free quote online on our website within seconds! Our system will automatically calculate the final price for windshield replacement, so you know exactly how much it will cost you.

Be sure to try it out, we worked really hard to deliver accurate prices for every vehicle in the United States! 🙂

At US Auto Glass, we have a chain of experienced and certified technicians who are trained to safely and effectively replace your car’s windshield.

We use the latest technology and equipment to ensure a perfect fit for your car. And, we offer a wide range of auto glass options to suit your specific needs. So, whether you need a new windshield or door window, US Auto Glass has you covered!


While it might seem like a daunting task, fixing a leaky windshield is actually not that difficult. You just need to have the right tools and know-how.

In this article, we’ve outlined three methods for how to fix a windshield leak – one for holes in windshield glue, one for stone chips, and one for deep cracks. If you experience a leaking windshield, don’t panic! There are solutions out there that will work for you.

And if you don’t feel comfortable doing the repairs yourself, US Auto Glass is always here to help. Have you tried any of these methods to fix your own leaky windshield? Let us know in the comments below!



Oliver Nordsve is a unique individual with bilingual skills; he speaks five languages and is a father of 4 lovely children. In his spare time, he loves to prepare big meals for the family, go for long walks and meditate every morning. He has worked in the auto glass industry for 15 years and is a company veteran. At carglass.io, he is the head of business development which, during his time, has evolved into a business with several branches globally. Oliver used to replace windshields on trucks and buses during his time with MAN.


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