Before we begin to explain why auto body shops cannot (or should not) guarantee rust repairs, we must first understand what rust is, what causes it, and how it affects your vehicle.


What is rust?

Rust is the oxidation of metals. It is a molecular transformation that breaks its integrity.

The two most common metals used in vehicles are steel and aluminum.

When steel rusts, it is formed from an electrolyte molecule that penetrates the layers and causes them to peel off. Corrosion usually occurs most quickly from saltwater.

The introduction of galvanized steel has significantly improved the anti-corrosion properties of cars since the late 1980s.

More and more vehicle manufacturers are using aluminum or hybrid panels, which are a mixture of metals to increase fuel economy.

What are the root causes of rusting vehicles?

When different metals such as aluminum and steel come into contact, they contaminate each other and start the rusting process.

Auto body shops must isolate vehicles that have different types of metal and never use the same tools on different metals.

Even small specifications of steel embedded in an aluminum can begin to create a white chalky distribution.

Paint on aluminum panels usually begins to peel off when it is also exposed to the electrolyte, such as seawater.

This looks like a white chalk residue that many people mistakenly believe they can simply clean and paint with no problem.

Metal oxidation

When your vehicle is manufactured, all bare metal surfaces are printed and sealed with thick enamel paint or powder coating that protects it from corrosion.

There are some metal parts on the undercarriage that has a transparent coating or nothing at all.

Many vehicles found on the floors of dealer showrooms have mufflers that are already rusted.

Powder coating is the primary method of protecting and beautifying exhaust manifolds and other hot parts because it resists heat.

Certain ceramic paints may offer protection of limited durability.

Damage to road particles

The main causes of oxidation are road wear.

Every time you drive, small stones and particles kick under the vehicle and open the door for them to penetrate when they cut or cut the paint.

The front fascia and areas near the wheels are particularly susceptible.

Floor trays are prone to rust because paint can break down from prolonged exposure to water.


Any area with a leaky seal can cause water seepage and corrosion. This includes headlights, the trunk, window seals and any accessories bolted to the body panels.

Will the rust return?

There is never a sure way to know if rust will return or not. There is no simple rust remover that cures everything and magically removes and prevents any additional rust.

Therefore, the auto repair shop does not provide a warranty for rust removal maintenance. Metal is often contaminated with microscopic particles that act like seeds, re-incubating and restarting the process.

Repairing rusted parts and treating them with rust inhibitors can slow the process down to imperceptible levels.

However, they don’t call severe oxidation “cancer” for nothing. It tends to spread because even a cell or other cells on the verge of rust formation can return it overnight.

Fix small spots prone to rust

If you find any scratches, nicks, or dents, you should quickly repaint it with a clear-coat nail polish or factory paint touch-up kit. These should be available as color matching kits at your dealer.

This can be done by rubbing the surface with sandpaper, grinding wheel, glitter or a Dremel bit to remove any visible rust stains.

Then prepare for body filler or touch-up the paint by wiping it down with mineral spirits to promote adhesion and bonding.