Here’s What Road Salt Does to Your Car

By Erie Insurance on October 18, 2019

When winter arrives, so do difficult driving conditions like whiteouts and black ice.

Road salt helps melt ice, which definitely makes the roads safer. However, there are some definite downsides when it comes to your car. . Read on to learn exactly how road salt works—and what road salt does to your car.


Salt—or in scientific terms, sodium chloride —lowers the freezing point of water. So while water normally freezes at 32 degrees Fahrenheit, water needs colder temperatures in order to freeze when it’s exposed to salt. The more salt you add, the more difficult it is for water to freeze.

The thing about road salt is it needs a little water to activate the process. Sometimes, road crews will pre-treat roads with a mix of salt and water called “brine.”Salt brine can keep ice from ever forming. If there’s a lot of snow and ice on a road, the brine will seep into the bottom layers, breaking the bond between the ice and the road. The remaining snow and ice will then float along the top of the brine, making it easy for any passing traffic to break it up for good.

In case you were wondering: Yes, it’s possible for the temperatures to be too low for road salt to work! Generally speaking, if the road temperature is colder than 15 degrees Fahrenheit, the salt won’t be able to penetrate the solid ice to start dissolving. When that happens, road crews might spread sand on top of the ice for better traction.


While road salt is doing good things for road safety, it’s doing something very different when it comes into contact with your car.

Salt creates chemical reactions that can corrode your car. This is especially true for any exposed metal.

Two car parts that are especially susceptible to corrosion and rust are the brake and fuel lines. That’s because they’re close to the undercarriage of the car, which takes the brunt of the road salt damage.


So what’s a driver to do? Fortunately, there are some tried-and-true ways to help protect your car from road salt damage.

  1. Take measures in the fall. Give your car a good wash and wax. For the best protection, apply a wax sealant over your wax. Modern ceramic coatings work best but, are also the most expensive.
  2. Have any scrapes, chips or rust spots repaired before the first snow falls.
  3. Keep your distance when driving behind trucks spreading salt or brine.
  4. Get regular car washes. Spray your car down at least once a week if you live in a snowy area. Invest in a wash that cleans the undercarriage of the car at least every few weeks or after a heavy bout of snow and/or ice hits your area. Consider a fluid film coating prior to winter for extra protection. Read more in this post about why winter car washes are worth the investment.
  5. Give an older car some extra TLC. Cars are especially susceptible to corrosion after being exposed to road salt for eight years or more, reports the National Highway Traffic Safety AdministrationGet more car care secrets in this post about how to keep a high-mileage car running.
  6. When spring arrives, consider a thorough exterior detailing job. Read more in this post about how to help your car recover from winter.

One way you can protect your car in any season is with the right auto insurance. Talk to an insurance professional like an Erie Insurance agent to learn more about getting the right coverage at the right price.