The Effects of Road Salt on Cars & How to Protect Your Vehicle from Salt Damage

Snow Covered Roads

In many parts of the country winter is going strong, pounding down on the roadways that drivers travel daily. Thankfully your local Department of Transportation (D.O.T.) is out in full swing plowing, sanding, and salting the roads to make it as safe a journey as possible. It’s common knowledge that snow and icy road conditions can cause car accidents. That is also why salt is used on the roads, since it helps to melt snow and ice on the roads, but it also provides some extra traction when combined with sand.

Washing your car in the midst of winter is important, and not just so it can look clean, but also to remove the salt that accumulates. Removing road salt used is the best practice to help prevent rust damage. Brake lines are typically another of the areas affected, so having them checked frequently is important.

Not all car manufacturers sell cars that are better equipped to handle road salt accumulation. CBS Minnesota quotes Paul Hagen, the owner and mechanic at Hagen Auto Body in Minneapolis, that washing your car in winter months is a necessity.

Why does a car rust from road salt?

Metal parts of a car come in contact with precipitation water containing carbon dioxide and oxygen. Road salt contains free-radical ions and they come into contact with the precipitation water. After extended exposure to oxygen, iron oxide forms, which speeds up the rusting process.

Snow Covered Rust

How does road salt work?

Road salt was first introduced in the 1930s as a combatant to make roadways safer for driving. It does this by a chemical reaction lowering water’s freezing point, melting ice so tires can make contact and get traction with the pavement.

It helps prevent the vehicle from sliding when ice is present on the road. The down side to this very important part of road safety, is it’s highly corrosive to vehicles and over time causing rust. The damage can be extensive, but being that it is an abundant, cost effective and easy to work with source, it is arguably the best choice.

Rust is one of the biggest threats road salt residue can cause for vehicles, with repeated exposure, due diligence by the owner is needed. Road salt affects the car’s paint causing corrosion, rust begins forming underneath bubbling up and the metal becomes brittle and flakey. Eventually the damaged area breaks free and if left untreated a hole can occur.

Since road salt promotes rust and can affect its mechanics, the undercarriage of a car or truck has multiple areas road salt can damage if left unmaintained. Locating affected areas can be difficult and having the car looked over by a professional is a good idea. From the frame to the hydraulic brake system, rust can do serious damage making the car unsafe to drive.

For example, the hydraulic brake system carries brake fluid to the brakes for them to expand. If salt causes damage to the line resulting in a leak(s), the brakes don’t work properly, or in some cases not at all.

The Fight Against Road Salt Car Damage – What can you do?

  • Wash your car as soon as possible after each snow or ice storm. At maximum every 10 days.
  • Wash your car when temperatures reach 40 degrees Fahrenheit or higher.
  • Washing your car in daylight hours gives it a better chance of completely drying before temperatures drop at night time.
  • Open and close all the doors, hatch and trunk after washing your car, and lock and unlock doors multiple times. This should be done as soon as possible to prevent freezing shut.
  • Avoid driving in deep snow; it packs against the bottom of the car. This can contribute to rusting and cause driving hazards.

The Finish on a Car – How can you protect it?

Tip: Rain and snow collect the pollutants in air (acid rain) covering your car. This can damage a car’s protective clear-coat finish.

  • Wash your car as soon as possible after each rain shower or snow storm.
  • Using a car wash that does not use recycled water, wash the undercarriage frequently.
  • Road salt collects in pools of water. Avoid driving in puddles.
  • If a paint chip is larger than the tip of a pen, repair it as soon as possible to avoid rust corrosion.
  • To protect your car, apply wax to your car at least every 6-months.

Applying Rust Proofing

Tip: Rust proof does not work on pre-owned used cars, only on new ones. When rust proof treatment is applied to a used car, it can trap existing moisture and dirt causing an increased risk of rust.

According to Bridgestone Tires, the American Highway Users Alliance found there is an 85% reduction in road collisions directly resulting from applying road salt when inclement weather conditions. People know the D.O.T. is providing an essential service and may not even mind getting caught behind those plow trucks, or that the salt being used is eating away at their car the moment it hits it.

Road salt is a part of life for those who live in wintery weather areas, it must be endured. This very successful road treatment product seems to be the favorite, and most effective combatant to provide safe driving condition.

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