Best Rust Prevention Spray for Cars: Boost Your Car’s Lifespan 

A rusting car is an eyesore, so protect it with these rust prevention sprays

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Every time you take your car out for a drive, you subject it to weather elements that depreciate its value. Maintenance costs can weigh you down, especially when you’re dealing with serious issues, such as rust. Fortunately, you can mitigate these costs by making small changes, like getting the best rust prevention spray for cars. This review will guide you in choosing the best rust prevention sprays that will keep your car in tip-top condition. 

  • Best Overall
    3M Professional Grade Rubberized Undercoating (Six Pack)
    Summary
    Summary
    The 3M undercoat is a versatile spray that’s suitable for all types of vehicles. It protects your undercarriage and has anti-corrosion properties.
    Pros
    Pros
    Its noise-deadening properties will make for smooth and quiet drives. It quickly dries out and does not run during application.
    Cons
    Cons
    You have to hold the can at a semi-flat angle during application or the spray will dissolve.
  • Best Value
    WD-40 Specialist Long-Term Corrosion Inhibitor
    Summary
    Summary
    A highly efficient spray that protects your car against extreme weather conditions. It comes with a straw for the best application.
    Pros
    Pros
    It forms a layer to guard against air and moisture. It is ideal for long-term outdoor use.
    Cons
    Cons
    It leaves a sticky residue that may attract dirt.
  • Honorable Mention
    Permatex Rust Treatment
    Summary
    Summary
    This spray forms a protective barrier you can paint over. It can be used with fiberglass and body filler.
    Pros
    Pros
    Application is very easy—simply spray it or brush it. It kills rust on all automotive parts.
    Cons
    Cons
    It has an overpowering smell. You also need to apply another primer over it before painting to prevent blistering.

Benefits of Rust Prevention Spray

  • Saves money. Rust can cause serious problems with your vehicle, and treating accumulated rust is an expensive venture. Rustproof spray for cars ensures you tackle the problem before it becomes a big financial drain. 
  • Maintains the resale value. Rust damages your car, lowering its value. If you protect your car against rust, you might get a better offer because it looks good and runs smoothly. 
  • Improves durability. Cars eventually wear down over time. Keeping your rust-free is one way to make sure it gives you great service for a long time. 
  • Reduces accident possibilities. Anti-corrosion spray for cars ensures that all parts of your car are well-maintained and functioning properly. If every component works as it should, chances of mechanical failure and accidents are minimized.

Types of Rust Prevention Sprays

Inhibitors

Inhibitors are specially designed to prevent rust on surfaces. They slow down the process of oxidation, which leads to rust. They should be used before rust appears, and the best rust inhibitors for cars are a great preventive measure, especially in humid areas.

Removers

Removers are considered some of the best-rustproofing sprays for cars. This is because, unlike inhibitors, you can spray them directly on rust. They bond with rust, and the resulting substance can be washed off with soap and water. You can also use removers as inhibitors. 

Primers

Primers form a base, which is a treated surface you can paint over. They are usually combined with removers to create powerful rust prevention sprays. Primers are bonding agents that create a bond between the surface beneath them and the paint applied on top. Their main job is to make the paint stick well to the surfaces.

Top Brands

3M

3M was founded in 1902 as Minnesota Mining and Manufacturing Company. The discovery of a low-grade mineral transformed the company into a global innovator with brands and products in more than 10 key industries. Today, it is a hugely successful company known for products such as 3M Professional-Grade Rubberized Undercoating

WD-40 Company

Headquartered in San Diego, Calif., the WD-40 Company was founded 65 years ago. It is a world-renowned brand that is popular for its home convenience products, especially its WD-40 line. One of its bestsellers is the WD-40 Specialist Rust-Release Penetrant Spray with Straw.

Permatex

Since 1909, Permatex has been at the forefront of the automotive industry. It produces car products for both residential and commercial use. It’s a trusted brand with a presence in over 80 countries. One of its best-selling products is, without a doubt, the Permatex Rust Dissolver Gel.

Rust Prevention Spray Pricing

  • $5-$10: If you are on a tight budget, this is a great place to start. A spray in this price range works as a rust converter for any metal surface. 
  • $11-$20: There are more options in this price range. Sprays come in 12- to 16-ounce cans and leave a clean finish. 
  • Over $20: Some of the best undercarriage rust protection products come in at this price point. Most rust preventers that cost over $20 can be painted over. Some manufacturers sell two or three sprays in a pack, so you get great value for your money.

Key Features

Corrosion Resistance

Even after you apply the spray, your car remains susceptible to corrosion due to daily wear and tear. It is crucial that you look for the best rust prevention spray for cars that forms an anti-corrosion film on the applied surface. This feature is particularly important if you are a frequent off-road user.  

Drying Time

The drying time separates the best rust stoppers for cars from the worst. After applying the spray on your car, you should give it about two hours to settle and dry. This is important if you are considering painting over the area. If the spray takes too long to dry, you may have to wait for hours—or days—before painting your car. 

Multiple Uses

Some sprays offer a 3-in-1 formula: a rust remover, a primer, and paint. They are the best products to stop rust on cars. However, if you are unsure about using a multipurpose spray, you can use a basic remover, apply the primer, and paint over the surface.

Other Considerations

  • Chemical components: Rustproofing products can cause damage to your hands over time. Fortunately, there are options that use friendlier elements, such as lanolin. To steer clear of harsh chemicals, check the labels for warnings. 

Best Rust Prevention Spray Reviews & Recommendations 2019

Best Rust Prevention Spray Overall: 3M Professional Grade Rubberized Undercoating (Six Pack)

3M Professional Grade Rubberized Undercoating (Six Pack)
Amazon

The 3M undercoating spray is one of the best undercarriage rust protection sprays for cars and trucks. One reason is that it doesn't run or sag during and after application. We also love its stand-out noise deadening feature. It is asphalt-based, something that makes it perfect for road noise control.

This pack contains six 16-ounce cans. Two of the cans are enough to cover an entire underbody, and you can store the extra ones for future use. The rust prevention spray leaves a black, glossy finish that makes your undercarriage less vulnerable to corrosion and abrasion. 

The 3M undercoating is a handy product you can use on most parts of your car. But as a precautionary measure, make sure you treat the rusted areas first. Applying it over rust can trap water and cause rust to damage your car parts from the inside. The application angle is also crucial. It will dissolve if you don’t hold it at a semi-flat angle.

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Best Rust Prevention Spray Value: WD-40 Specialist Long Term Corrosion Inhibitor

WD-40 Specialist Long Term Corrosion Inhibitor
Amazon

If you are looking for good value, the WD-40 Corrosion Inhibitor will not disappoint. A single six-ounce can cover about 10 square feet of your car, depending on your application method. It is among the best rust inhibitors for steel, as it binds to metal and safeguards it from moisture and air.

The spray forms a protective film where it’s applied and can last up to a year with above-average usage. It performs well outdoors and keeps corrosion at bay. The straw it comes with offers a controlled spray that penetrates hard-to-reach areas common in car parts. To test the true grit of the WD-40 Inhibitor, use it in humid conditions. 

It performs well in all seasons, although you may need to reinforce it during winter. We also feel the can is very small and maybe insufficient for your needs. Additionally, the sticky residue the spray leaves can act as a dirt-trap.

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Best Rust Prevention Spray Honorable Mention: Permatex Rust Treatment

Permatex Rust Treatment
Amazon

If you are searching for the best rust prevention spray, your search may stop when you get Permatex Rust Treatment. It has an easy application process and kills rust on all automotive applications—from trucks to hatch covers. It also removes rust on agricultural equipment but can only be used on surfaces 200-degrees Fahrenheit and lower.

One of the traits that make this spray great is you can use it over rust. You will not need to apply a pre-cleaner before application. Its two main ingredients, Tannic acid, and 2-Butoxyethanol, are organic extracts. When sprayed, they form a film on the rusted surface and create a good base for painting. 

But as much as it is a useful product with multiple uses, it has its drawbacks. For example, you have to give it time to completely dry. You will know it’s dry if it forms a protective coating on the sprayed area. You also need to wear the appropriate gear because it has a strong odor. 

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Tips

  • When using rust inhibitors, it is vital to know which ones require prior preparation of the rusty parts. Not all sprays can be used directly on rust. Some work as preventers while others work as treatments.
  • Be sure to check whether your rust prevention spray can be used with paint. Although the sprays leave a clean finish, painting over the surface afterward might be ineffective. Also, confirm whether it's safe for bodywork. 
  • Always wear the right gear. Rust preventers for cars can have a strong odor that may overwhelm you. A pair of gloves and a nose cover may be very useful. 
  • Make sure you get extra cans. This will ensure you cover every part, and you can store any additional products for future applications. 
  • If you aren’t sure of the effect, test the spray on a small area first. 
  • Depending on the car part, you can choose the most effective application method. Spraying is the top technique, as the formula gets to all the nooks and crannies. However, there are situations when you may need to consider applying the formula using a cloth. 

FAQs

Q: Which is the best rust prevention product?

A: This depends on the surface. Some products are specifically made for automotive applications. However, some are multipurpose and can be used on kitchen sinks and bathtubs, too. The best rust prevention spray is one that can be used in all areas susceptible to rust. 

Q: Can these rust removers be used on household products?

A: Anti-corrosion sprays for cars have harsh chemicals that might not be suitable for food-grade household items. You can use products such as CRC Calcium Lime Rust Remover to clean household items. DIY home remedies for rust removal—such as vinegar, baking soda, and acetic acid—also work well.

Q: Can rust removers be used over porous surfaces?

A: Rust prevention sprays are suitable for porous surfaces since they trap moisture. However, you will need more for the best results. 

Q: Can rust inhibitors be applied on areas that get hot, such as exhaust pipes?

A: Unless stated otherwise, manufacturers do not advise applying these sprays on areas that exceed 200 degrees Fahrenheit (93 degrees Celsius). 

Final Thoughts

Our pick for the best rust prevention spray for cars is the 3M Professional Grade Rubberized Undercoating (Six Pack). It works on undercarriages, fenders, floor pans, and wheel wells, and it also reduces road noise. 

If you are on a budget, get the WD-40 Specialist Long-Term Corrosion Inhibitor. It can block rust and corrosion for up to a year and offers the best of both worlds: preventative maintenance and protection in corrosive environments.

Ever had a bad experience with car rust? Share your experiences and solutions in the comments section.