The Best Undercoating Products to Keep Your Vehicle Rust-Free (2024)

Updated: January 23rd, 2023

We earn commissions from purchases you make using links in our articles. Learn more.

The Best Undercoating Products to Keep Your Vehicle Rust-Free (1)

If you are the kind of driver who prefers to keep your vehicles for many years, you will know well that rust is one of the most significant obstacles to keeping your car or truck roadworthy. Rust is the result of a chemical reaction that occurs when untreated metal is exposed to water or moisture-laden air, conditions that frequently exist in many coastal locations. And if you live in a part of the country where snow and ice are a regular part of winter, you will have noticed that the salt used to treat slippery roadways accelerates the corrosion process.

While many new vehicles leave the factory with some degree of rust protection, if you want your vehicle to remain rust-free for as long as possible, you must treat it annually with an aftermarket corrosion prevention product. One of the most common types of these is undercoating. When applied to your vehicle’s undercarriage, the best undercoating products will help prevent rust-related damage to floor panels and critical structural and suspension components. Although there are many professional companies that provide rust protection services for your vehicle, some of the best undercoating solutions come in convenient packaging so that you can apply them to your vehicle yourself.

As you might expect, there’s a lot of variety out there, so choosing the right product solution can be a daunting task. That’s why we’ve compiled a list of the best undercoating sprays so you can keep your vehicle rust-free for years to come.

For more information on the best undercoating products, refer to our table of contents.

1. Editor’s Pick: Rust-Oleum Professional Grade Undercoating Spray

Here’s a product that does exactly what it says on the can, which is to provide protection for your vehicle against the ravages of rust and other damage that can occur on the road. Rust-Oleum is no newcomer to this field: it was created about 100 years ago based on the discovery that oil spilled on the metal deck of a boat inhibited the formation of rust. We figure if a product is good enough to work in an unforgiving marine environment, you can also trust it to protect your car from winter road salt.

This is a rubberized spray that you apply just like spray paint, but as it dries, it turns into a thick, damage-resistant coating. Rust-Oleum says the product takes about an hour to dry to the touch. Each can of Rust-Oleum covers between 10 to 15 square feet, so you will definitely need more than one can if you hope to cover the entirety of your vehicle’s underbody. Thankfully, you can buy this undercoating in a six-pack as well as single cans. The can itself is designed to spray at any angle—even upside down.

Pros

Provides sound deadening as well as rust protection; dries quickly, can sprays at any angle

Cons

Some buyers say the product appears little different from Rust-Oleum’s less-expensive, standard-grade undercoating, multiple cans required for good coverage

2. Best for Large Projects: Fluid Film Undercoating

If you require a large volume of high-quality undercoating, we recommend this product from Fluid Film. The company says its undercoating was created for industrial applications, primarily on large ships and offshore oil rigs, where corrosion is a massive problem. No wonder you can buy this product in a huge, five-gallon pail.

Despite the size of the container, you are meant to spray, not brush, this product onto your vehicle. Because it is quite thick, it’s recommended that you apply this undercoating in warm weather when the product is in its most fluid state. One buyer said they had the best success using Fluid Film’s professional-grade spray gun. And while this product’s price may be off-putting, consider that this pail costs about what you’ll pay a professional to apply undercoating to your vehicle—and you’ll get multiple applications out of this amount of the product. Fluid Film says its formulation is non-toxic.

The only reason we didn’t make this product our Editor’s Pick is because it's less practical for DIY application than the Rust-Oleum corrosion inhibitor that made the number one spot.

Pros

An effective way to protect your vehicle from corrosion, good value, non-toxic

Cons

Comes in an unwieldy, heavy pail, you must buy a separate sprayer to apply this undercoating

3. 3M Professional Grade Rubberized Undercoating

The number three spot on our list of the best undercoating products goes to another recognizable name in vehicle protection, 3M. It comes in a convenient spray can that goes on black and dries to a rubberized, flexible surface that will protect your vehicle’s metal from corrosion-causing salt and damage from other road hazards.

As is the case with many undercoating products, this one also provides some sound-deadening, so your vehicle will be a little quieter after you apply 3M’s undercoating. While it is recommended that you apply this spray to a clean, dry surface, you do not need to prime the metal first as you would if you were painting it.

Sold in a six-pack of spray cans, your purchase should be enough to coat the underside of a small vehicle; one buyer said they used three cans to cover the bottom of a pickup truck cab. Another buyer recommends buying more than you think you’ll need as this spray goes on thick.

Pros

An effective product from a recognized name, convenient six-pack of spray cans

Cons

You will probably need more cans than you originally estimate, ultimately, it wouldn’t cost that much more to have your car professionally undercoated

The next undercoating product we found to recommend to you is this spray-on formulation from Rusfre. Packaged in a one-gallon container, Rusfre says its undercoating is designed to be used with the company’s own applicator gun. That will add extra cost to your job but will ensure the product goes on your vehicle as intended and provides the best possible protection. On the plus side, this container should be enough to completely coat the underside of almost any passenger vehicle.

Like most other undercoating products, Rusfre’s is rubberized, so it provides some sound-deadening qualities along with protecting your vehicle from rust and other damage. The liquid contains bound fibers to help it bond to your vehicle’s metal and prevent it from chipping, cracking, or peeling after it dries. While Rusfre makes no claims about its undercoating being non-toxic, it does say it is asbestos-free, making it that much safer for you to use.

Rusfre recommends that you apply its undercoating at room temperature (about 68 degrees F) or warmer after stirring and shaking it well.

Pros

An effective product packaged in a high-value and convenient one-gallon jug, provides sound deadening qualities

Cons

Require spray gun is expensive, can take up to a week to fully cure

Our final undercoating recommendation comes from Woolwax, which is made from lanolin, a naturally occurring wax secreted by wool-bearing animals like sheep. While Woolwax stops short of claiming its undercoating is “all-natural,” it does say the product contains no solvents and is non-hazardous and environmentally friendly. In theory, that makes it potentially less harmful to you if you accidentally inhale its vapors or get the product on your skin; however, Woolwax says the real benefit is that the lack of solvents helps prevent its undercoating from evaporating over time. That means that once you apply it, your vehicle will be protected for longer.

Woolwax makes its undercoating thick enough to prevent dripping but fluid enough to spray using one of its proprietary sprayer designs, which you have to buy separately. Once you have applied this undercoating, it will cure and thicken to a gel-like consistency. That means it stays flexible and will “heal” itself if the coating is scratched.

While this Woolwax formulation is black, you can also buy a clear version. Woolwax also makes an undercoating product in a spray can for more convenient application.

Pros

Almost no smell, no solvents reduces evaporation, does not wash off easily

Cons

Must be applied with proprietary sprayer at extra cost, one-gallon can is not a particularly convenient package

How and when should you apply undercoating?

The Best Undercoating Products to Keep Your Vehicle Rust-Free (7)

Photo credit: Virrage Images / Shutterstock.com

Generally, you’ll get the best results by applying undercoating in milder weather, at temperatures around 68-degrees F or warmer. That’s because while these products come in liquid form, they are thick and get even thicker when they’re cold. So even though you’re likely using undercoating to protect your vehicle primarily against road salt used in winter weather, you should apply it well before cold weather arrives.

Among the more forgiving products is Rust-Oleum’s undercoating spray, which the company says you can apply at temperatures above 50-degrees F.

What safety precautions should you take when applying undercoating?

Most undercoating products contain chemicals that can cause you serious harm if you inhale them or get the product on your skin. When applying undercoating, we recommend that you wear rubber gloves, an N95-type mask to prevent you from inhaling vapors, and eye protection.

Also, be sure your workspace is well ventilated. If you’re working in your garage, open the door; even better, park your car on the driveway while you’re applying undercoating.

Should you choose a product that comes in a spray can, or in a pail or jug?

As with most products, you’ll get a better deal on undercoating if you purchase it in larger quantities. However, before you buy something like a five-gallon pail of Fluid Film’s product in the number two spot on our list, consider your needs. If you only have one vehicle to protect from rust, buy it in spray cans for convenience’s sake.

Products that come in a pail or jug require you to buy a separate spray gun, which is an additional cost to consider. If you own several vehicles to which you will apply your own undercoating every year, that extra cost may be worthwhile. But otherwise, you’ll appreciate the convenience of buying spray cans; you can find spray can multi-packs of undercoating products, an option that will save you a few dollars over buying individual cans.

What are some side benefits to applying undercoating?

Among the most-touted side benefits of rubberized undercoatings is that they possess sound-deadening qualities. After you apply one of these products to the underside and wheel wells of your vehicle, you should notice a minor reduction in the amount of road noise in the cabin, especially at highway speeds.

Also, some undercoating products will also help prevent fasteners from rusting stuck. If you choose an undercoating that promises this, it should make some future repairs, like replacing worn suspension parts, easier by helping to prevent rusted nuts and bolts from breaking when you try to loosen them.

Recent Updates:

November 23, 2022: Updated product links.

We are committed to finding, researching, and recommending the best products. We earn commissions from purchases you make using the retail links in our product reviews. Learn more about how this works.

Photo credit: Greg Brave / Shutterstock.com

The Best Undercoating Products to Keep Your Vehicle Rust-Free (2024)

FAQs

The Best Undercoating Products to Keep Your Vehicle Rust-Free? ›

Protect Your Vehicle's Underside With Durabak

What is the longest lasting car undercoating? ›

Woolwax® will absolutely last longer and provide protection longer than any other annual maintenance undercoating. Nothing lasts longer than Woolwax®. It does not wash off like other lanolin films. Woolwax® is available in Straw (clear) and Black colors.

What is the best underbody rust protection? ›

The best underseal 2024 at a glance:
  • Editor's pick: Bilt Hamber Dynax UC – Buy from Amazon.
  • Best for after a refurb: Liqui Moly Bitumen Underbody Protection – Buy from Amazon.
  • Best value underseal: Simoniz Black Under Guard – Buy from eBay.

Which undercoating is best for cars? ›

  • Best Overall: Dynatron 544 Dyna-Pro. See It. ...
  • Best Value: Penray 4424. See It. ...
  • Most Versatile: 3M 03584. See It. ...
  • Honorable Mention: Rust-Oleum Automotive Professional Rubberized Undercoating. See It. ...
  • Best Rust Preventative: POR-15 Rust Preventative Coating. See It. ...
  • Best Temprorary: Fluid Film Rust and Corrosion Protection. See It.

What can I put under my car to prevent rust? ›

Protective coatings for vulnerable areas – Apply protective coatings, such as rubberized undercoatings or rust-resistant paints, to susceptible areas like the undercarriage and wheel wells. These coatings provide an extra layer of protection against rust-causing elements.

Which is better rust proofing or undercoating? ›

If you want your vehicle to look nice use a rust, proofing product. It you want your vehicle to last, use an undercoating product or service.

What are the disadvantages of rubberized undercoating? ›

Rubberized formulas have a dried film that is often hard, arid, and brittle, making it exceptionally smooth and durable but allowing air and moisture to seep underneath the coating, leading to rust formation and corrosion.

Is ziebart rust proofing worth the money? ›

While it may seem like a more inexpensive option at a glance, results aren't guaranteed to last 365 days, and this service will have to be redone completely each year at full cost with little to no warranties available to safeguard the investment you've made in your vehicle.

Which undercoat is best? ›

Water-based undercoats are great for larger surfaces like your wall and ceiling, as they'll also tend to use water-based paints. Conversely, with doors and skirting boards needing oil-based paint, an oil-based primer/undercoat is your best option.

Can I undercoat over rust? ›

Older cars can see more benefit from undercoating, but any existing rust will need to be removed before the undercoating is applied.

What is the best rust prevention for cars? ›

Best Rust Converters And Inhibitors
  • FDC Rust Converter Ultra: Best Brush-On Rust Converter.
  • Rust-Oleum Rust Reformer Spray: Best Affordable Rust Remover.
  • POR-15 Rust Preventive Coating: Best Brush-On Rust Preventative.
  • Corroseal Water-Based Rust Converter: Best Overall.
Jan 5, 2024

How to rust proof your undercarriage? ›

Here's what to do—and what not to do—to keep car-killing corrosion at bay.
  1. Apply a Coating to the Underbody. ...
  2. Pressure-Wash the Underbody. ...
  3. Touch Up Those Paint Chips. ...
  4. Buy Rubber Floor Mats. ...
  5. Store Your Car During the Winter.

Will WD-40 stop rust from spreading? ›

It won't CAUSE rust, it will form a protective barrier to oxygen in the air, preventing further rusting (oxidation). It can't displace rust already on the surface, so cleaning the item prior to application will work much better.

How long does undercoating last on a car? ›

How long does undercoating for cars last? If you live in a cold, snowy climate, near the ocean, or in other rust-prone areas, undercoating should be reapplied each year. Since road salt and de-icing treatments can make corrosion worse, it's best to undercoat your vehicle just before winter weather begins.

What is permanent undercoating? ›

Undercoating is the sprayed application of a wax or rubber-based composite onto the entire underside of the vehicle. It's designed to create a rust-proof layer between the underside of the vehicle and the water, ice, and salt of the road. Undercoating provides a more comprehensive protective layer for your vehicle.

What does the military use for undercoating? ›

ValuGard VG-160 Military Spec Solvent is a high performance solvent based wax based coating for body panels vehicles.

How long does ziebart rust proofing last? ›

Total Appearance Protection

Genuine Ziebart Rust Protection and Undercoating: this ensures that the underside and all upper body panels of your vehicle remain rust-free. It's inspected and renewed once a year.

References

Top Articles
Latest Posts
Recommended Articles
Article information

Author: Nathanael Baumbach

Last Updated:

Views: 6204

Rating: 4.4 / 5 (55 voted)

Reviews: 94% of readers found this page helpful

Author information

Name: Nathanael Baumbach

Birthday: 1998-12-02

Address: Apt. 829 751 Glover View, West Orlando, IN 22436

Phone: +901025288581

Job: Internal IT Coordinator

Hobby: Gunsmithing, Motor sports, Flying, Skiing, Hooping, Lego building, Ice skating

Introduction: My name is Nathanael Baumbach, I am a fantastic, nice, victorious, brave, healthy, cute, glorious person who loves writing and wants to share my knowledge and understanding with you.