How to Treat Corrosion and Rust from Continuous Exposure to Road Salt

These steps will help you remove and treat rust and corrosion. Remember, though, that severely rusted parts may require replacement.

Catching rust in its early stages saves hundreds of dollars later on. Inspect every inch of your vehicle for:

• surface rust: thin, flaky, or dusty orange coating
• scale rust: bubbling paint, thicker rust layers, pitted metal
• penetrating rust: holes, weak metal, visible structural damage

Surface and scale rust can often be treated at home. If you find penetrating rust, though, take your vehicle to a garage. The affected components may need to be replaced.

Before you treat rust, you must remove all the salt. Otherwise, even the best coating won’t stick properly. You can try the following methods to clean the affected areas:

• A high-pressure undercarriage wash targets hard-to-reach pockets.
• Soap and hot water break down salty film.
• Foam cannons or degreasers are most effective on heavily caked salt.
• Brushes for wheel wells and rocker panels help you get into those hard-to-reach spots.

Avoid washing your car on extremely cold days: water can freeze in seams and cause cracking.

Once the vehicle is clean and dry, the next step is prepping the damaged metal.

For surface rust:

1. Sand the area lightly until shiny metal is visible.
2. Use a wire brush to pull off flakes.
3. Wipe the area clean with rubbing alcohol or degreaser.

For scale rust:

1. Use a stronger wire wheel or rotary tool.
2. Remove all bubbling paint and thick rust.
3. Continue until the metal is smooth and stable.

If rust has gone through the metal, a body shop or technician may need to cut and replace the affected area.

Rust converter is one of the most effective tools against ongoing corrosion. It chemically transforms rust into a stable, paintable compound. This stops the oxidation reaction in its tracks. Quality rust converters will:

• turn the rust black as they cure
• seal the surface
• prepare the metal for coating
• prevent further rust spread

They’re especially useful for wheel wells, frames, undercarriages, and seams that see a lot of salt spray.

After treating the rust, you need a protective barrier so salt can’t attack the metal again. Here are some of the most common protective treatments:

• Oil-based rustproofing creeps into seams and weld points and displaces moisture. It’s excellent for older vehicles or those already showing rust, but requires annual reapplication.
• Rubberized undercoating is ideal for the undercarriage and wheel wells. It forms a durable barrier and offers long-lasting protection. However, only apply it to rust-free or treated metal.
• Cavity waxes work best for inside panels, door cavities, and rockers. They coat hard-to-reach inner metal surfaces to prevent hidden corrosion.

A technician can recommend the best combination based on your vehicle’s age and condition.

Once the rust is treated, sealing and painting the area ensures long-term protection. Follow these steps:

1. Apply a primer suitable for metal.
2. Add one or two layers of rust-resistant paint.
3. Finish with a clear coat for durability.

This prevents moisture and salt from contacting bare metal again.

Treating corrosion is important, but preventing it is even better. Incorporating these habits into your winter maintenance can minimize further damage from road salt:

• Wash your undercarriage at least once per month in winter.
• Avoid driving through deep slush when possible.
• Repair scratches and stone chips quickly.
• Pair annual rustproofing with your spring or fall inspection.
• Store the vehicle in a dry garage.

These steps dramatically slow down salt-related corrosion. For more advice, visit your local NAPA Auto Partsshop. Our experts will be happy to point you in the right direction.