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Why Do Windshields Crack? What Causes It and How You Can Avoid It.

Why Do Windshields Crack? What Causes It and How You Can Avoid It.

The windshield plays an important role in the vehicle. Not only does it provide protection to the drivers and passengers from rain, strong wind, dust, or snow, but it also provides safety since it prevents the drivers and passengers from being plunged from the vehicle in the event of an accident. The windshields are usually strong but there are instances where it just cracks for no reason. It can be a hassle since windshield cracks can become bigger and it cannot be repaired. But why do windshield cracks? Aside from being hit by a direct force, windshields can crack because of temperature changes, structural defects, sunlight, poor installation, mechanical stress loading and a lot more. 

Auto Repairs Are EXPENSIVE


 

Keep in mind that windshields are strong. It is said that car windshields now possess a high-level of strength. They are not so fragile anymore. So if one morning you see your windshield cracked, know that it is caused for a reason since it does not just crack. So why do windshields crack? Let’s find out!

 

Why Do Windshields Crack? – Why did my windshield crack for no reason?

 

Modern car windshields are usually built using laminated safety glass. This type of glass is stronger and safer than normal annealed glass since it is involved in three different layers. Its two outside layers are composed of annealed glass sheets and a special strip of Polyvinyl Butyral or PVB for the middle layer that holds the two panes together. In the event of an accident and your car windshield breaks, the laminated glass’ broken shards will remain stuck to the PVB interlayer on impact and will not fly off. It is for this reason that the windshields of the modern vehicles are known to be more safe and secure against many damaging elements.

 

If  windshields are so strong, many might wonder why do windshields crack? There are a lot of reasons why windshields crack and here are some of them.  

 

  • Change in pressure.  

 

Pressure changes caused by heavy storms and winds or sudden gust of winds can result in a cracked windshield. If you put something heavy on your windshield, it can also cause it to crack. Cracks caused by stress due to pressure changes just appear out of nowhere. It can appear on the edge of your windshield and the center of the crack usually feels smooth when you touch it.  

  • Temperature changes. 

 

The windshield glasses tend to contract and expand when exposed to sudden temperature changes. The science behind this is that the different sections of the glass have been heated up at different speeds. Usually the middle section is heated up at a slower speed while around the edges are at a faster speed which is why the glass also contracts and expands at different rates. 

 

Changes in temperature is one of the most common reasons why windshields crack. It could be triggered when you are using cold water while washing your car during a very hot day. Attempting to defrost an icy windshield by pouring hot water directly on it can cause it to crack, too. Always be mindful of your windshield and keep in mind that sudden fluctuations of temperature can cause stress to it. Be cautious of the surrounding area’s temperature before you do or pour anything on your windshield to prevent it from developing cracks. 

  • Prolonged exposure to sunlight.

 

Prolonged exposure to sunlight can heat up the metal and other materials of your car. It can also heat up the edges of your windshield faster than the middle part which can cause cracks to appear on your windshield. To prevent this from happening, make sure that you park your car in the shade, out of direct sunlight.

 

  • Structural weakness or defects.

 

One possible reason that answers the question, “why do windshields crack?” is that the windshield might have a structural defect or weakness. Manufacturing defects can happen even to auto parts. This can happen when the glass is heated and cooled during the manufacturing process and there have been residual stresses that are discovered along the windshield’s perimeter. These residual stresses can cause the windshields edges to become weak and prone to cracks. 

  • Poor installation.

 

There are instances where the windshields of your car have not been installed properly, even by the professionals. Although a cracked windshield caused by poor installation is a rare case, it can happen. When your windshield has not been installed properly, it can vibrate due to a loose fit that can cause stress on the glass. The stress on the glass is enough to cause your windshield to crack.

 

  • Mechanical stress loading.

 

Stress-loading can happen when there are too much distortions or flexing on the car’s body that can be caused by improper vehicle lifting with a jack. Due to the improper lifting, the body of the car might have been twisted excessively causing its windshield to crack.   

 

  • Minor damages. 

 

Your windshield might have previous minor damages that you have forgotten or didn’t know about. When you are dealing with windshield damages, know that even a tiny chip or a thin fracture can cause the windshield to crack. No matter how small or thin the damage is, it tends to expand over time resulting in cracks to appear on your glass. 

  • Accidents.

 

If you have been involved in an accident in the previous years, it could be the reason why a crack suddenly appeared on your windshield. The accident might have caused stress to your car’s internal structure and since the car’s windshield also gives structural support to the car, the stress on its internal structure can lessen the strength of your windshield.  

 

After the accident, you might not notice any sign of cracks or windshield damage. But over time, the cracks might start to appear since the structural integrity of the windshield has weakened. If your windshield has weakened, even the slightest of stress could bring about unwanted cracks on your windshield. 

 

These reasons are some of the common reasons why windshields crack all of a sudden. Some other reasons include a direct force that often comes from flying gravels while driving, tree branches that fell on your windshield, and hail. 

 

Why Do Windshields Crack? –  How do I prevent my windshield from cracking? 

 

After finding out why do windshields crack, knowing how to prevent your windshield from cracking can be useful, too. It is because a damaged windshield can be a hassle since you might need to have your windshield replaced. 

 

Since all it takes is one small crack to damage the whole windshield, it is important that you know how to take care of it and avoid potential cracks or damages. Here are some of the ways that can help you prevent your windshield from cracking.

  • Always keep your distance.

 

When you are traveling, may it be on the highway or city streets, make sure that you always keep your distance and give plenty of space between you and the vehicle in front of you – more so if the vehicle in front of you is a large truck or a dump truck. Although most of these trucks have mud flaps, rocks and other debris can still be kicked and it might land on your windshield and cause a crack.   

  • Choose to take the less-traveled road.

 

Taking the less-traveled and less-trafficked road can reduce your chances of having your windshield damaged or cracked by a stray rock or pebble kicked up by other vehicles. If you are not running late for a meeting or other appointments, you can take the less-busy road and be free from the potential rock-kicking vehicles.

 

  • Drive carefully and slowly.

 

Driving carefully and slowly can reduce the chances of accidents and the chance of your windshield being hit by a flying rock. Although the crack can happen when that rock hits your windshield, it is the forward motion of the car hitting the car that amplifies the impact. You need to drive carefully by keeping a safe distance behind large vehicles and drive slowly to lessen the chances of a flying rock causing severe damage to your windshield. 

 

In an event where you are experiencing a hail or driving in one, driving slowly can also reduce the force of the impact on your windshield and can keep other accidents from happening. When you know that there is hail coming, it is best that you don’t drive or use your car at all and park your car in the garage or somewhere with a strong shade to prevent your car from taking a direct hit. Plus, it is also not recommended that you drive in a dust storm. 

  • Avoid extreme temperature change.

 

Prolonged exposure to the sun can cause your windshield glass to weaken or become brittle and as the sections of the glass heat up at a different speed, it can cause a crack to appear. If you feel like your windshield has a weak spot or is starting to develop a crack, do not expose your car out in the sun but park it in the shade instead. Parking your car in the shade can prevent potential cracks from expanding and at the same time, protects it from any further damage. 

 

When the temperature is very cold, do not try to heat up your car abruptly. You can try to turn the defroster up bit by bit. Remember that extreme temperature changes can cause your windshield to crack. 

  • Always check your windshield.

 

You might not notice that you have a cracked or chipped windshield – especially if the crack is tiny or thin. You won’t be able to notice these kinds of cracks if you don’t check it. That is why it is important to alway check your windshield regularly. If you find any chip or a small crack, it is best that you have it fixed immediately since refilling it and repairing it while it is still small can avoid it from turning into a severe problem that might require a windshield replacement. 

 

Why Do Windshields Crack? – How big of a crack can be repaired on a windshield?

 

Why do windshields crack is often asked by the car owners when they, themselves have experienced the problem – a cracked windshield for no reason. Windshields don’t crack for no reason, there is always an underlying problem that causes it to crack. There are cracks and chips that can be repaired and there are some that might require you to replace your entire windshield. 

 

What are the cracks and chips that can be repaired? How big of a crack can be repaired on a windshield? The answer really depends on these three different factors.

 

  • The sizewindshield chips that are smaller than a quarter and cracks that are up to three inches long are said to be easy to repair. The sizes can vary depending on the location of the damage and the capability of the shop doing the repairs.   

  • The depth – like mentioned above, the windshield has three layers – the glass outer layer, a plastic interlayer, and a glass inside layer. It will be impossible to repair a chipped or cracked windshield if the damage has penetrated through the outer and inner layer of glass.  


  • The location – the location of the damage is the one that can really determine if the damage is still repairable or not. It is because there are damages or cracks that can compromise the structural integrity of the windshield even if it is not that big. Damages that intersect more than one outer edge of the glass is one of them. In an event of a car rollover, the windshield can provide up to 60 percent of structural strength and it is for this reason that any cracks that can compromise its structural integrity can’t be repaired. A windshield replacement will be the best option. 

 

Why Do Windshields Crack? – Final Word

 

Knowing the answer to the question “why do windshields crack?” can help us understand why it happens. When we understand why it happens, we will then know how to prevent it from happening. The car’s windshield is as important as any other parts of the car. It also keeps the drivers and the passengers safe by protecting them from the elements, giving structural support to the car, facilitating airbag deployment, and preventing passenger ejection.