Salt lowers the freezing point of water, so many cities and towns spread it across roads to help melt ice and keep drivers safe during the winter. But while salt is great for eliminating slippery driving conditions, it’s terrible for cars. Along with lowering water’s freezing point, salt can accelerate rust and corrosion on your car’s metal components, and it can damage your car’s paint finish, too. Luckily, there are ways to protect your car during the winter and limit the damage caused by road salt.
Prepare Your Car Before Winter
Before any winter weather arrives, take the time to wash and wax your car. Cleaning off dirt and debris will help keep your paint in good condition, and the blemish-free surface will help protective wax adhere to the paint.
Of all your vehicle’s parts, the metal chassis is the most exposed to salt. Consider paying for an underbody wax to help protect it. Some auto shops swear by oil undercoatings, which undoubtedly prevent rust, but applying them is a messy job and not environmentally friendly.
Make sure all of the vehicle’s drainage holes are clear, too. These small, often pin-size holes can be found at the base of the windshield (near each corner), at the bottom of each door, and occasionally in the rear quarter panels. As the name suggests, drainage holes are designed to allow water to escape from the vehicle after a good wash or a rainstorm, but if the holes are blocked, standing water will collect within your car’s bodywork, leaving it susceptible to rust.
Take the time to repair any visible paint chips. Your car’s paint is specially designed to protect it from the elements, so any metal peeking through represents a doorway for rust.
Finally, if you own a collectible car or a car you want to keep for an exceptionally long time, consider putting it in storage over the winter, rather than driving it on salty roads.
Keep Your Car Clean During Winter
Protecting your car doesn’t stop once winter starts. In fact, the sloppy road conditions and cold temperatures will make keeping your car clean a near-constant effort. To help, try to avoid driving through puddles or deep snow, and when you do start to see slush and debris collecting on your vehicle, take it through a car wash. It’s best to time these car-wash visits when temperatures inch above freezing, and make sure to dry it well after each wash.
Most car washes use recycled water in early stages of the wash cycle. But avoid car washes that use recycled water in the final rinse stage. There’s a lot of salty, sandy, dirty grit in this water, and it can damage your paint (not to mention, negate the effect of that spray). You will typically have to ask the car-wash manager to find out whether the service uses clean, fresh water for the final rinse.
Even if your car doesn’t look dirty, be sure to regularly spray its undercarriage to wash away any salt and dirt. Pay close attention to your vehicle’s doors, fenders, hood, and tailgate. These areas are often the most susceptible panels to rust.
Beware of Warmer Temperatures
Salt is always bad for metal, but it’s especially bad during warmer temperatures. Rust forms when the air interacts with moisture on metal, causing that metal to oxidize. Metal oxidizes faster at warmer temperatures, so if the thermometer rises above 40 degrees Fahrenheit, make sure you wash your car, and quick.
The Bottom Line
Salt is bad for cars and bad for the environment, but very good at keeping roads dry and safe. Enjoy dry, grippy roads without risking damage to your car by repairing paint chips and washing and waxing your car before your town starts laying salt on the road. Once winter hits, the snow has started to fall, and the roads are covered with salt, continue to keep your car clean and free of slushy, salty dirt, particularly if the weather turns warm.