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Choosing The Best Car Undercoating Spray – Top 7 That Will Protect Your Vehicle Undercarriage

Before we talk about the best car undercoating sprays, let’s tackle the root of the problem in the first place: rust.

Rust will literally eat away metal. If you can imagine the undercarriage of an old car, you would probably find a lot of rust formation. If left unchecked, rust will consume the entire undercarriage, and this affects the overall integrity of your vehicle.

Product Name Quality Price Our Rating
3M 03584 Professional Grade Rubberized UndercoatingA+$4.8 stars 
Rust-Oleum 248657 Automotive 15-Ounce Undercoating SprayB+$$4.5 stars 
Bondo 737 Rubberized Undercoat AerosolB$$4.2 stars 
CRC 05347 Rubberized Spray UndercoatingB$$$ 4 stars
Permatex 81833 Heavy Duty Rubberized UndercoatingB$4 stars 
Penray 4424 Rubberized UndercoatA$$ 4.5 stars
PlastiKote (272-6PK) Black Rubberized UndercoatingB$$$ 4 stars

**Below, you’ll find our more detailed reviews, but you can also click the links above to see current prices or read customer reviews on Amazon.

Rust Is Not Your Best Friend

underbody rust

In fact, even the smallest presence of rust on the underbody is something that you should be concerned about, especially if you drive a newer car. New cars are treated with a coat of rust proofing at the factory, so you should be worried if you see rust on your 4-year old SUV.

If you live in places like Hawaii or South Dakota, then you should definitely pay attention because it doesn’t matter if your car is brand new or just a silly old rust bucket. Salt and corrosion go hand in hand, and if you live near the sea or if you drive your car in harsh weather then rust formation is inevitable.

It’s like death and taxes. They will come, but nobody knows when. It’s as sure as the sun rising in the East. Well, you get the picture.

That’s the main problem with rust. You wouldn’t notice that they’re already there, eating away at the precious metal of your ride. Rust moves fast, too. Even just a slight dent on the undercarriage can cause rust to form in a matter of hours.

However, all is not lost. You can either depend on the services of a professional, or you can do it yourself. But there’s a problem.

Professional Undercoating Is Expensive

Professional undercoating services will usually cost hundreds of dollars, and you will have to wait a day or two for the job to get done. Professionals will place your car on a hoist, remove all the wheels, spray the undercarriage with pressurized water, degrease the entire floor pan, and let it dry before applying the undercoating.

But if money is tight, then why not do it yourself? You will thank yourself in the end, because you are protecting the value of your investment while improving the NVH of your ride.

That’s right. Undercoating will seal all the nooks and crannies of the undercarriage, thereby preventing road noise from intruding inside the cabin. Not a bad deal in exchange for a couple of hours of work on a lazy weekend, right?

The 7 Best Car Undercoating Sprays Reviewed

1. 3M 03584 Professional Grade Rubberized Undercoating

The 3M Rubberized Undercoating spray is perfect for cars, trucks, SUVs, and recreational vehicles. This asphalt-based undercarriage spray is excellent for wheel wells, under the fenders, quarter panels, and even under the hood.

The no-run formula makes the product easier to apply since you don’t need to worry about cleaning drips on your garage floor.

The 3M Rubberized Undercoating spray will protect your vehicle undercarriage from rust, corrosion, and abrasion caused by salt, rain, stones, dents, and dings.

The rubberized coating provides durable protection and sound deadening properties by sealing small cracks, holes, and undulations of an old undercarriage. The rubberized spray will create a protective barrier to seal out grit, moisture, and grime, the three elements that cause rust and corrosion on all metal components.


  • Sprays easily like paint
  • No-run formula means less mess
  • ​Excellent sound deadening properties
  • Friendly price


  • Slightly unpleasant smell when wet

2. Rust-Oleum 248657 Automotive 15-Ounce Undercoating Spray

You can easily protect metal surfaces from rust and corrosion by using the Rust-Oleum Undercoating spray. The trusted formula of this rubberized spray will provide a durable barrier against rust formation on the undercarriage.

This product is made in the USA to ensure quality and ease of use. The rubberized coat will remain soft when dry, and the surface can be prepped for the application of paint whenever applicable.

For maximum protection against rust and corrosion, Rust-Oleum recommends 2 thin coats for every application. Drying time will usually take 1 to 2 hours depending on the ambient temperature.


  • A trusted name in rust prevention
  • Made in the USA
  • The rubberized coat is paintable


  • The surface needs to be degreased thoroughly, otherwise, the product will not stick to the surface
  • Recommends 2 coats for maximum protection

3. Bondo 737 Rubberized Undercoat Aerosol

The Bondo 737 is an asphalt-based product. This means that the surface is non-paintable when dry. But this is not necessarily an issue is you’re going to use this on your undercarriage anyway unless you’re planning to paint the undercarriage.

All it takes is a single coat of Bondo 737 undercoating to protect the underside of your vehicle from rust, corrosion, and metal damage caused by road debris.

The formula is guaranteed not to drip, sag, or run. Simply spray for an even coat. The rubberized texture of this undercoating spray will also seal the undercarriage so your car will ride smoother and quieter, even on dreaded cobblestone roads and surfaces with loose gravel.


  • No drip formula
  • Resists running and sagging
  • Sound-deadening qualities


  • It takes too long to dry

4. CRC 05347 Rubberized Spray Undercoating

The CRC Rubberized Spray Undercoating is a bubble-free formula designed to protect the undercarriage and diminish outside noise.

The formula is designed not to peel or crack even after many years of exposure to harmful road elements such as salt, moisture, and harmful road debris.

This undercoating spray goes on thin, but you only need a single coat of CRC to experience a vast improvement in silencing road noise and tire roar.


  • One-coat protection against rust and road noise
  • Good price
  • Easy to use


  • Might take too long to dry depending on the weather

5. Permatex 81833 Heavy Duty Rubberized Undercoating

The Permatex Heavy Duty Undercoating spray is all an all-purpose product that seals, protects, and insulates the underbody of your vehicle.

The professional-blend formula is ideal for automotive, home, or shop use. You can use this product to seal gutters, roofs, and drainage systems. This is perfect for the DIY enthusiast!

The improved rubberized formula will resist moisture and rust, protect the underbody from damage, and improve the NVH characteristics of your car, truck, or SUV.


  • Good insulator for the car
  • Perfect for home use
  • Easy to use


  • Pricier than other brands
  • Lengthy drying period

6. Penray 4424 Rubberized Undercoat

The Penray Rubberized Undercoat is a quick-drying black and rubberized formula that provides a waterproof coating. This undercoating spray will protect against rust, extreme heat and cold, corrosion, fumes, dust, and road salt.

The Penray undercoating spray also provides a paintable surface when dry. This product is perfect for the undercarriage, frame, and wheel wells of your car. The rubberized spray also acts as an insulator to reduce road noise.

The Penray rubberized Undercoat is designed to rust-proof, seal, and protect all metal surfaces. This product is also ideal for DIY projects both inside and outside the home.


  • Paintable surface when dry
  • Durable rubberized coat
  • ​Easy to apply
  • ​Perfect for DIY jobs at home
  • Good price


  • Requires 2 coats to protect the surface
  • Takes a bit of time to dry

7. PlastiKote (272-6PK) Black Rubberized Undercoating

The Plastikote Black Rubberized undercoating spray is an easy to use and easy to apply product that provides protection against moisture, rust, and corrosion.

This underbody spray is easy to apply. Perfectly designed to coat the wheel wells, weld joints, gas tank, doors, floor pans, and quarter panels of your vehicle to resist moisture and the formation of rust.

The rubberized coating provides a flexible and durable barrier that dries quickly. No drips, no mess, and no fuss.


  • Quick-drying formula
  • Durable rubberized coating remains flexible
  • Easy to apply


  • Prohibitive price

Underbody Cleaning Tips

 Spray to clean the car undercarriage

1. You need to clean the undercarriage before using an underbody protective spray. Use a pressurized washer to remove dirt, mud, dust, and other debris.

2. If there is a lot of grease on the surface, you need to use a degreaser before applying underbody spray. If not, the product will not stick to the surface properly, no matter how long you leave it to dry.

3. If there is a lot of rust on the metal surface, take time to remove rust and corrosion before applying undercoating spray. If not, the rubberized formula might do more harm than good, as it will seal the moisture into the metal, effectively increasing the chances of rust formation. You want to keep the moisture away, not trapping it in the metal.


3M Rubberized Undercoating is the best car undercoating spray
Our choice: The 3M Rubberized Undercoating is the best car undercoating spray.

All of these 7 products are the best undercoating sprays for DIY applications. However, the 3M 03584 Professional Grade Rubberized Undercoating stands out from the rest.

We like the fact that the 3M Rubberized Undercoating only requires a single coat to provide maximum rust protection and sound-deadening capabilities. We also like the price as the 3M Undercoating is in the middle of the price range.

Thinking about preserving the value of your car? Some people take care of the paint and the interior, but those who really know cars will also take the time to protect the undercarriage using the best car undercoating sprays.

About George Bradley

George is an enthusiastic blogger and an auto mechanic expert whose mission is to provide the readers with the best tips, guides, and recent events in the automotive industry. He has been involved in researching on various topics that are essential to the car owners, especially when it comes to an understanding, maintaining and handling their vehicles.

3 thoughts on “Choosing The Best Car Undercoating Spray – Top 7 That Will Protect Your Vehicle Undercarriage”

  1. The Rust-Oleum undercoat spray is worthless .I work in retail where we sell about a dozen cans of it a day and have heard bad things about it not lasting more than a few months .So I bought 6 cans myself and did the underneath of my truck and it all washed off in 5 weeks .It’s a waste of money even though it’s the cheapest option at less than $4.00 a can . The Rust-Oleum spray truck bed liner is a way better product .Now Rust-Oleum products are not Oil Based even the reps from the company say their products are only about 60% of the lasting quality they use to be .

  2. Unfortunately, both look and feel of the vehicle get corrupted over time. Sometimes, rust can also catch the metal body. We may ignore looks, but we can’t neglect rust. No doubt, rust is the number one rival of a metal surface. So, if once the intermediary gets accumulated by rust, it will not only damage that particular portion but also its neighborhood briskly and severely. In that case, we need a spray which will prevent the metal body from rusting and also make the car look fresh and relentless. Here, the author has listed some of the best undercoating sprays. It is most favorable for those motorists, who don’t want to make the spray job by a professional. Though it is good to perform the same task by an expert, I think if someone is capable to do it on his own then he can do it simply by selecting any of the above spray materials.

  3. All of these products are the same in application and function; fine for heavy underbody and frame parts; but the real rust to fight is inside the doors and rocker panels; and none of these will help you there, as they don’t reach or run into crevices you cant see ! Ziebart was always the best but is no longer in business; so the next best would be Eastwood interior frame coating; as you can apply it with a long tube and dispersing tip; included with the spray can ! It will easily reach into rockers and door coating areas you cant see !


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