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Corrosion and rust are some of the worst threats faced by your car. They will ruin your vehicle’s looks and undermine the durability and performance of affected parts. In particular, your car’s undercarriage is vulnerable to rust because it usually comes into contact with corrosive substances like chemicals, dirt, and water on the road.

Fortunately, you can stop rust on the car undercarriage by applying rustproofing. There are several ways to rustproof your car, such as oil-based sprays and undercoating. Read on to find out how to protect the undercarriage from rust.

What is Rustproofing?

Rustproofing is a general term for any treatment that provides undercarriage rust protection for your car. Usually, the treatment applies a protective layer on the undercarriage.

The term rustproofing itself can also refer to treatments that use oil-based products. This usage includes both drip and dripless oil sprays.

spraying a drip oil spray to a car component
Rustproofing is a general term for any treatment that provides undercarriage rust protection for your car, and drip oil spray is the most popular rustproofing method available.

What Does Rustproofing Do?

Rustproofing prevents the electrochemical reaction that creates rust. Most rustproofing types block direct contact between metal and corrosive oxygen. The new electronic method uses electricity to disrupt the electrochemical process that forms rust.

By preventing corrosion from taking place, rustproofing makes the various parts of the undercarriage last longer. If the component already shows signs of rusting, rustproofing can prevent rust from spreading further.

Types of Rustproofing

There are several proven approaches to undercarriage rust protection. Each type comes with strengths and weaknesses. Think carefully about your situation before choosing the treatment that best suits your car.

Here are the different types of rustproofing:

Drip Oil Spray

Drip oil spray is the most popular rustproofing method available. It involves applying an oil-based material to the undercarriage. The oil flows easily, allowing it to enter many areas in your vehicle with ease.

To facilitate the application of drip oil spray, you must drill holes into various parts of your vehicle’s undercarriage. The doors and fenders are two of the items that will require drilling.

Drip oil can take up to 48 hours to dry. During this time, the oil will leave stains on the ground under your car. It’s recommended to park your vehicle on the road to avoid staining your driveway.

Dripless Oil Spray

Another popular rustproofing treatment is the dripless oil spray. It is sprayed on the undercarriage and requires holes drilled into specific body parts to ensure the oil can reach as deeply as possible.

Unlike its drip oil counterpart, dripless oil dries up faster, reducing the risk of runoff staining the ground. It also hardens, forming a moisture seal that feels firm and waxy. The seal adheres to your car’s frame, providing long-lasting protection against corrosion.

Tar-Based Spray/Undercoating

What is undercoating? Also called tar-based spray, it started out as a way to reduce the noise made by the vehicle during driving. It uses a different substance to protect your car’s undercarriage from rust.

Undercoating a car involves spraying a tar-based substance to the undercarriage. When the tar dries, it solidifies into a layer that provides lasting protection against the elements.

However, moisture can penetrate the undercoating as time passes. Furthermore, the hardened tar might fracture, which will compromise its protection. You should inspect the undercoating for cracks every year to see if your vehicle needs a new treatment.

Electronic Rust Protection

The electronic rust protection system is an optional feature usually offered at your dealership, which will install an electronic module for a fee.

Once installed, the module generates a weak electrical current through your car’s body. This current stops rust from forming in areas where oxygen comes into contact with steel.

This approach enjoys several advantages over spray-based rustproofing and undercoating methods. For one thing, it doesn’t require a physical layer to protect your vehicle from moisture. Furthermore, you don’t need to drill into your car’s body like with drip and dripless oil sprays.

However, many drivers have reported that the electronic rust protection system does not work as well as oil-based and tar-based sprays. The technology might need more time to mature before it can achieve the same level of corrosion-preventing performance as spray products.

Rust Proofing vs Undercoating

Given the issues with electronic rust protection, the choice usually boils down to oil-based rustproofing or tar-based undercoating. Both approaches offer benefits and drawbacks that you should consider carefully before choosing what feels best for your car.

Advantages of Rustproofing

Drip oil spray offers the most thorough coverage of your car’s undercarriage. Thanks to its low viscosity, the oil can penetrate more parts.

Meanwhile, dripless oil spray combines the benefits of drip oil spray and undercoating. It can reach almost as many parts as drip oil, and like undercoating, dripless oil also hardens into a protective layer.

Advantages of Undercoating

Undercoating provides permanent protection against corrosion. It also does not drip after application, so you don’t have to worry about stains on the ground.

Furthermore, undercoating doesn’t require drilling holes in your car’s body parts. You get to protect the undercarriage without potentially ruining your vehicle’s looks.

person wearing a hazmat undercoating a car
Undercoating a car involves spraying a tar-based substance to the undercarriage, and when the tar dries, it solidifies into a layer that provides lasting protection against the elements.

When Should You Apply Rustproofing to Your Car?

Have you decided that your car needs further protection against corrosion and rust? You should pick the best time to apply rustproofing and undercoating. The exact time can vary depending on how new or old your car is.

New Cars

One of the very first things that you should do with your new vehicle is to ask the dealership about rustproofing or undercoating it. They will usually offer the service as an option.

At such an early point in its lifespan, the new car is in mint condition, unblemished by rust. Rustproofing or undercoating the undercarriage will extend the car’s pristine state for much longer than on its own.

Used Cars

Used vehicles already went through years of exposure to the elements. However, they can still benefit from rustproofing or undercoating.

Summer and spring are the best times to apply rustproofing to a used vehicle, as these seasons are the driest parts of the year.

In states that experience winter, road salt has been washed away by rain or removed by humans by the time spring comes around, so there won’t be any corrosive salt left on your car’s undercarriage.

Is Rustproofing or Undercoating Worth It?

Rustproofing and undercoating come with a financial cost. Before you commit to either, consider if you can afford the treatment. Keep in mind that your car might need repeated treatments in the future.

Furthermore, take a long, hard look at your vehicle. A bargain-bought secondhand car may not be worth rustproofing or undercoating. Conversely, a high-end vehicle you intend to drive for a decade deserves long-lasting corrosion protection.

If you own an older car, always apply rustproofing or undercoating treatment to its undercarriage. Unlike modern cars, older vehicles don’t use galvanized steel that resists corrosion. Your classic car will benefit from rustproofing.

Do you live near the ocean or in a state that experiences lots of rain or snow? Rustproofing or undercoating is a must to deal with the corrosive effects of seawater or moisture in those areas.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : Car Body , DIY
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