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Few things are more annoying than a cracked car windshield. Even if it’s not in a location that obscures your view, it just looks unsightly. It can also be dangerous if the crack continues to spread and the glass shatters. But can this happen spontaneously to your car? Here’s what we found out.

What is spontaneous breakage?

A broken windshield, potentially a windshield to spontaneously break through various means like heat.
Broken windshield | Getty Images

To begin, yes, your car windshield can spontaneously break. The good news is that this isn’t an everyday event. In fact, it’s pretty rare. The other good news is that it’s not quite as spontaneous as you might think if it’s ever happened to you.

So, what is a spontaneous break? MS Glass Outlet states, “A spontaneous break means the glass develops a crack, seemingly out of nowhere. You may even see it happen right in front of your eyes. Or, you may go to sleep one night and wake up with a cracked windshield the next day.”

This can also happen when you do something as simple as closing the door or driving over a road in desperate need of repair. There may not seem to be any rhyme or reason for it, but it’s not just karma or fate. There is definitely a reason why your glass broke.

Rising temperatures can cause your windshield to break

Heat can greatly damage vehicles, from fading leather seats to causing drive belts to crack and even damaging your battery. It can also cause your windshield to spontaneously break.

In most cases, there’s already a tiny crack in the glass, which is so small it’s gone unnoticed up to this point. It could be caused by a rock hitting your window or any number of other factors. But when the sun beats down on the glass and temperatures begin to rise, that once tiny crack begins to spread.

The heat can be tricky, as it will cause the glass to heat up more on one side than the other. This causes the crack to spread on the side that is heating up while it remains the same size on the other. For those of us who have felt a crack on the outside of the window but can’t feel it on the inside, this is how that happens.

If you allow this to continue without having the glass fixed, it can shatter when the right pressure is applied.

What else can cause your windshield to break?


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Heat isn’t the only factor that can cause your windshield to crack. Cold temperatures can do it as well. 

Another factor that can contribute to your glass shattering is installation. Tools used to set it in place may cause little nicks that go unnoticed but grow over time.

Something else you need to consider is if the windshield you’re going to install. It is vital that the design of the glass is made for your vehicle. It doesn’t make sense to install a windshield designed for a Porsche in a Jeep. That may sound a little far-fetched, as the two have little in common, but the same applies when looking at windshields that are highly similar in shape and size.

While it’s impossible to predict when your glass will begin to crack, it’s essential to take it in for repairs as soon as you notice it. A crack may start, and never spread again. It may also spread so far that it stretches from one end of the windshield to the other and never shatters.

However, that’s not something you should risk. Windshield glass repairs often don’t take that long, and if you have good insurance, it may even be inexpensive. Getting it repaired as soon as possible will save you heartache and possibly injury later on down the line.