How to Stop Rust on a Car or Truck

The iron worm, the red menace, metal corrosion, whatever you call it, rust is one of the inevitable problems that can affect your vehicle.

While rust (like death and taxes) is inescapable. There are steps you can take to extend the life of your vehicle.

There are three key steps required to stop rust on a vehicle:

  1. Understanding Rust
  2. Preventing Rust
  3. Treating Rust


What Is Rust?

Rust is the layperson’s text for the chemical process called oxidation. In this process, iron molecules react with oxygen in the air to create iron oxide. This process is accelerated by the presence of salt, especially when it’s dissolved in water.

Because of this, water that gets trapped in unseen pockets of your vehicle will dissolve, leave behind contaminants and speed up the oxidation process.

This is why vehicles in the Northeast and mid-west that get exposed to more snow and use road salt are more rust-prone than vehicles in drier areas.

Types of Rust
Surface Rust

protect against surface rust

Your vehicle’s paint doesn’t just make your vehicle look good. It’s also your first line of defense against rust. When your vehicle is exposed to UV-radiation, rain, snow ice and regular wear and tear, the finish starts to crack. Over time, moisture can seep into these cracks are create rust that develops on the surface of your vehicle, just under the paint.

Scale Rust 

Left untreated, rust will continue to penetrate into the metal surface of your vehicle. Because rust molecules are bigger than the iron or steel in your vehicle, the rust expands and continues to expose more of the base metal below. This can cause a rough, pitted type of damage called scaling that further damages the metal surfaces of your vehicle.

Penetrating Rust

After prolonged exposure, steel is converted to brittle iron oxide and holes form. As the rust creates these holes, they continue to expose more of your vehicle’s metal to rust and can affect the structural and craft integrity of your vehicle’s panels and frame.


As the saying goes, the best defense is a good offense. The best way to keep rust from damaging your vehicle is to not let it get a foothold in the first place.

Keep it Clean

Rust can only affect your vehicle when you allow corrosive materials to stay in place for extended periods of time. Cleaning your vehicle on a regular basis is the first line of defense. This is especially true during the winter when your vehicle can get exposed to road salt and get damaged by snow, ice and winter UV radiation. If you don’t want to take your vehicle to the vehicle wash, you can also clean it at home. Even spraying your vehicle with a mixture of baking soda and automotive soap can neutralize the acidic effect of salt and other chemicals. Use sparingly one tbsp. of baking soda should be sufficient for the undercarriage of your vehicle.

Keep it Covered

If you leave your vehicle parked outside, you run the risk of water and other elements damaging your finish or pooling on the surfaces of your vehicle. Putting a cover on can help keep rust at bay. Look for covers that keep rain and moisture from penetration and cover as much of your vehicle as possible. Also, make sure your cover provides adequate ventilation so that condensation can’t accumulate and continue to contribute to rust.

Treat and Coat

While there is no such thing as a guaranteed rust prevention treatment, adding a water-resistant coating to the surface of your vehicle can help keep water from penetrating your finish.

Another option is to apply an undercoating to protect your undercarriage from corrosion. Using a rubberized undercoating rather than a “clear coat”. The rubberized coating is more durable and creates a stronger water-resistant seal.

Ideally, an undercoat should be applied when the vehicle is new, however, if you want to add this layer of protection after it’s left the dealership, clean the undercarriage thoroughly. If rust has already begun to accumulate you’ll need sand or grind it off and then paint and prime the undercarriage.

Also remember, no treatment or coating will last forever, remember to reapply at regular intervals to maintain.

Inspect Regularly

Checking your vehicle over on a regular basis can allow you to catch rust accumulation and prevent it from spreading. When inspecting, check the:


Give your vehicle’s paint a regular once over. If you see dark spots in the paint, scratches or dings that show signs of rust, or paint that is blistering from below, these may be signs of rust build up.

Wheel Wells

These are frequent problem areas for rust build up because they aren’t in place sight. Most tire manufacturers recommend that you rotate your tires every 6,000 miles (10,000 km), so when you perform this maintenance, use the opportunity to check for rust as well. If there is too much mud to see clearly, spray with a hose to clean out the well before inspecting.


If your vehicle has a metal bumper, inspect these as well, checking the outside and inside surfaces and the mountings. This is especially important for older vehicles where metal bumpers can rust faster than the body of the vehicle.

Joints and Panels

Another place where rust can accumulate is in the joints and spaces between panels where sections of your vehicle meet. Even if your vehicle is made with non-rusting materials, the mounting brackets that hold panels in place can still be at risk.


The underside of your vehicle will usually take the most punishment during the winter because it is unpainted and directly exposed to snow, ice and road salt.

Checking beneath your vehicle during routine oil changes or tire rotation is a good way to nip any problems in the bud.


Scrape and Sand

If you find rust building up in paint cracks or crevices, gently scrape away using a single-edged razor blade or fine-grain sandpaper. For larger painted areas, a brush with stiff (not-metal) bristles can also help to remove rust. You can also use coarse sandpaper to grind the rust off large areas that are out of sight and not surrounded by paint.
Rust remover can help, but should only be applied after you get the loose rust off the surface, the rust remover can then help to get into the areas where the rust is in contact with your vehicle’s metal and loosen its grip on your vehicle.

Remember, to work inward from the edges. Otherwise, you risk additional damage to the rest of your vehicle’s finish.

Apply Rust Arrestor

After you’ve removed all the rust, apply a rust arrestor. This will help to keep the rust from spreading further and provide an extra layer of protection.

Prime and Paint

Once your rust arrestor has fully dried, you can prime and paint the affected area to restore your vehicle’s finish.

Consult a Professional

If your rust damage is extensive, and there are visible holes in the body of your vehicle, it may be time to take it to a body shop.

Get a few estimates first and then compare the cost against the blue book value of the vehicle. If the cost to repair outstrips the vehicle’s value, it may be time to move on to another vehicle.

Protect against rust damage


While rust is unavoidable, taking the right steps to understand, prevent, maintain and repair your vehicle will allow you to extend its life, and get the greatest value for every mile that you drive. No matter how bad the weather.

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