The machines in a car wash are designed to clean your car, but they have some faults. Notably, some car wash bristles retain debris that scratches and causes swirl marks on car exteriors. I suppose it’s reasonable to fear that car washes can do further damage to your car.
A car wash cannot break a windshield as long as it functions properly. The machines in car washes are not powerful enough to break tough windshield glass. Car manufacturers install windshields that resist shattering even when subjected to huge forces.
This article will explain why you shouldn’t worry about your windshield breaking in a car wash. I will also look at the slim likelihood of a crack forming on your windscreen in a car wash. Finally, I’ll advise you on what to do if a car wash damages your windshield.
Can a Car Wash Break a Windshield?
Some automatic car washes require that you be in the car as the machines clean your vehicle. Therefore, the prospect of a windshield breaking while inside the car wash can fill one with dread. Water, chemicals, and the machines used in the process can cause injury and damage the car’s interior.
A car wash cannot break a windshield because windshields are built to withstand the forces inside a car wash. The brushes can damage antennas and side-view mirrors but can’t break the windshield. Manufacturers toughen windshield glass to reduce the likelihood of breakage.
It’s a little-known fact that lengthwise glass fiber is five times more robust than steel. However, glass is brittle, making it easy to break.
However, scientists have found ways to make glass hard enough to fit on cars and airplanes.
Windshield glass comprises three layers: two layers of glass sandwiching a tough plastic layer. Even if the outer layers shatter, the people inside remain safe as the glass sticks to the plastic layer.
Furthermore, car manufacturers use tempered glass on windscreens. Manufacturers create tempered glass by heating it and exposing it to blasts of cold air.
The outer surface shrinks faster than the inner surface, compacting it inward and strengthening it. Furthermore, it ensures that the glass breaks in small, relatively harmless pieces instead of large shards that are far more dangerous.

Therefore, it is improbable that your car’s windscreen will break due to the roller brushes, clothes, and water jets of an automatic car wash.
Your car windscreen can withstand the force of a hammer before letting anything get inside. Even if, by some freak accident, something breaks through your windshield during a car wash, you are unlikely to get seriously injured.
A study by M.D. Richard Carlton found that the probability of injury decreased significantly after car manufacturers placed a plastic layer between windshield glass. The injuries reduced in frequency and severity because of the tougher windshield construction.
Can a Car Wash Crack a Windshield?
You might sometimes see a car drive into a car wash with no visible cracks and come out of the other side with a visible crack on the windshield. The obvious culprit is the car wash, but you shouldn’t blame the car wash that quickly.
A car wash could crack a windshield because, theoretically, the temperature differences between the water and outside temperatures can increase the likelihood of the glass weakening. However, it’s highly unlikely to happen.
Rapid changes in glass temperature can cause it to crack. Windshield glass exposed to blazing summer heat will undergo stress if suddenly exposed to cool water inside a car wash. Similarly, hot water on a cold windshield can cause it to expand rapidly, stressing it.
However, unless the temperature changes are rapid and extremely severe, your windshield won’t break.
Everything changes if there’s an existing crack on the windshield. A run through a car wash can aggravate an existing crack. The crack is a weak point that may get weaker under the stresses of a car wash.

An existing crack will be more vulnerable to the temperature changes described above. Rapid expansion or contraction of the glass can cause stress cracks originating from the existing crack.
Car washes introduce soap and water onto your car at high pressure. Soap and water can seep into the crack, later expanding and increasing the crack.
Furthermore, the machines in the car wash exert pressure on the windscreen, which can worsen the damage. Additionally, drying using the high-powered air dryer can weaken the glass further.
Handwashing is a bit safer but can also aggravate existing damage, especially if the damage went unnoticed.
Unfortunately, most small cracks occur on the edges of the windscreen where it is weakest, making them difficult to spot. Drivers often discover the crack after an automatic car wash made it worse.
What To Do if a Car Wash Has Damaged Your Windshield?
Small cracks on windscreens can happen easily: All it takes is for a flying rock chip to hit the vulnerable edges of your windscreen. An automatic car wash can then stress the glass, making the crack more apparent.
If a car wash has damaged your windshield, repair the damage or replace the windshield immediately. You will increase the damage and risk your safety by driving with a damaged windscreen.
Most car washes would refuse to repair damage caused to your windscreen unless a gross malfunction of the car wash caused the damage. You’ll find that most car washes have signs warning customers that they aren’t liable for car damage.
Therefore, call your insurer to determine if your insurance package covers windscreen damage.
Some states – for example, Florida – require insurance companies to waive deductibles for windscreen repair. Therefore, you don’t pay a dime for windshield repair or replacement.
Even if your insurer doesn’t cover the repair or replacement cost, you shouldn’t drive a car with windscreen damage. It hurts to repair damage that you didn’t cause, but the risks of failing to remedy the issue are far more significant.
A large enough crack can impair your visibility, making it difficult to drive. Cracks outside your line of sight can impair vision by directing the sun’s glare into your eyes.
Furthermore, you risk increasing the crack as the windshield comes into contact with air and small rocks. Additionally, the laws in your area may prohibit driving with a cracked windscreen.
If, for whatever reason, you ignore the crack, park the car away from direct sunlight until you get it fixed. However, do not drive with a crack that impairs your vision.
A crack that’s longer than 12 inches (30.48 cm) is too long and will most likely require you to change the windscreen.
Driving with a cracked windscreen limits how you use your car’s heater. Subjecting the glass to rapid changes in temperature will stress the crack; therefore, ensure that the changes in temperature in your vehicle happen slowly.
Furthermore, avoid jolts that can rattle the windscreen – close the car door gently; drive slowly over bumps and rough roads.
The simpler and safer option is to have the crack repaired or the windshield replaced. A mechanic will advise you on the best choice for your vehicle.
Key Takeaways
Sources
Indiana public media: What Makes Windshield Glass So Tough?
Windshield Experts: Modern Car Windshield: How Strong Are They?
Auto Glass City: Can I wash a car with a cracked windshield?
The Journal of Trauma: The changing character and management of soft tissue windshield injuries
Carpool car washes: Yikes, where did that crack come from on my windshield?
MS Glass Outlet: A Guide to Car Washes and Windshield Crack Prevention
Glas Tek Windshield Repair: Can a drive through car wash crack your windshield?
Quora: I noticed a crack in my windshield after leaving the carwash, what should I do?
Glass.com: Can you wash your car if your windshield is cracked?
Volkswagen of Marion: Can You Get Your Car Washed with a Cracked Windshield?
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