How Does Road Salt Work?
Road salt works by lowering the freezing point of water, which helps to prevent ice from forming on road surfaces and makes it easier to melt existing ice. The primary compound used for road salting is sodium chloride, commonly known as table salt.
Here’s how it works:
- Freezing Point Depression: When salt is spread on roads, it dissolves in water (such as moisture or melted snow) to form a saltwater solution. This solution has a lower freezing point than pure water. For example, pure water freezes at 32 degrees Fahrenheit, but a saltwater solution might freeze at 20 degrees Fahrenheit or lower, depending on the concentration of salt.
- Melting Ice: When the temperature of the road is slightly below freezing, the salt helps to melt the ice by lowering the freezing point of the water, causing the ice to melt into liquid water even though the temperature is below 32 degrees Fahrenheit.
- Preventing Ice Formation: If the salt is applied before a snowstorm, it can prevent the snow from sticking to the road or prevent ice from forming. As the snow begins to fall and interact with the salty surface, it won’t immediately freeze, giving plows time to clear the roads.
- Effectiveness at Different Temperatures: Salt is most effective when the temperature is around 20 to 30 degrees Fahrenheit. Below that, its effectiveness diminishes, and other materials, like sand or more specialized de-icing compounds (e.g. calcium chloride), may be used.
However, road salt isn’t perfect—it can be less effective in very cold conditions and may also have environmental impacts, such as harming plant life and affecting water quality when it runs off into rivers and streams.
What Does Road Salt Do to a Car?
Road salt can have several negative effects on a car, primarily due to its corrosive nature. Here’s how road salt impacts your vehicle.
- Corrosion of Metal Parts: The biggest concern with road salt is its ability to cause rust and corrosion, especially on the car’s undercarriage, frame, and exposed metal parts. When salt mixes with moisture (snow, rain, or ice), it creates salty brine that can accelerate rusting, especially in areas where water can pool and sit on the vehicle, like the wheel wells, undercarriage, and suspension components.
- Damage to Paint: Road salt can also damage the vehicle’s paint job. As salt particles stick to the paint, they can cause small chips and scratches. When the salt reacts with moisture, it can create a chemical reaction that leads to fading and peeling of the paint.
- Brake System Issues: Salt can also affect the brake system. It can cause the brake components, such as calipers and rotors, to rust, which could lead to decreased braking performance or potential failures over time if not maintained properly.
- Damage to Rubber Components: Salt can degrade rubber parts like seals, hoses, and weatherstripping. This can cause leaks and cracks, which, in turn, can lead to other mechanical issues.
- Electrical Components: The salt brine can also find its way into electrical connections and wiring, which can lead to corrosion or short-circuiting if left unchecked.
How Can I Protect My Car?
There are several ways you can protect your car from the effects or road salt damage:
Wash your car regularly during winter, especially under the chassis, to remove salt buildup.
Waxing you car before the winter season creates a protective barrier against salt.
Rustproofing treatments can help to create an additional layer of protection for the car’s metal parts.
Check the undercarriage for any signs of rust or corrosion and address it promptly.
Keeping your car clean and maintaining it properly can significantly reduce the damage caused by road salt over time.