They Did Not Want To Do The Work To Properly Protect This 2024 Toyota Says This Expert―The Differences Between The Different Undercoats and What You Should Expect From Having Your Car Undercoated.

This is the season and the reason why cars rust as badly as they do―winter road salt; a problem not to take lightly because once it starts, rust never sleeps and eats away at your car or truck frame with the ferocity of termites in a Southern home.

And if you live within the Rust Belt region and have recently bought or will buy a new car very soon, you should be just as concerned about rust as a car's reliability rating and fuel economy. For example, the article’s header image is a good example of the fix you never want done for a rusted frame to keep your car on the road and out of the scrapyard.

Here's a Harbor Freight tool recommendation with tips on how to use it, for when rust becomes a critical repair issue on that old car or truck.

Where and What is the Rust Belt Region?

The term "Rust Belt Region" was originally coined as an economic label before being included geographically due to bad rust conditions stemming from harsh winters in the Midwest and Northeast regions, where the sheer volume of road salt overwhelms many cars.

According to the Encyclopedia Britannica:

Rust Belt―Geographic region of the United States that was long the country's manufacturing, steelmaking, and coal-producing heartland but that underwent dramatic industrial decline that resulted in widespread unemployment, increased poverty, decay, and population loss. Because the Rust Belt is defined by similar economic experience rather than by natural borders, its boundaries are debated; however, it is generally viewed as encompassing a large part of the Midwest (Indiana, Illinois, Michigan, Missouri, Ohio, and Wisconsin) along with Pennsylvania, West Virginia, and portions of New York.

In other words, cars from the Rust Belt are synonymous with economic and physical decay and can be a problem for new car owners living there.

When is there too much rust? Find out with a Toyota Tacoma rust problem demonstration that shows why even the cleanest looking of these popular models can have a hidden rust problem.

Common Solutions to Problems Don't Always Work―And Can Make the Problem Worse

Just as the old saying "The best-laid plans of mice and men" infers the truism that many common solutions to problems don't always work…and sometimes even make a problem worse.

This week's recent video from the Rustless Rides YouTube channel reveals that having your vehicle professionally undercoated is no guarantee your vehicle's undercarriage is protected from rust. In fact, you may have just paid someone to make your car or truck even more likely to develop a rust problem.

According to the host:

"It takes time and experience to properly undercoat and protect your car, truck, or SUV. Knowing how the vehicles are constructed and assembled is key to properly protecting them from rust and corrosion, a skill most places lack.

I walk you through this video and show you the areas that were missed and that were not even attempted to be undercoated. They did not want to do the work to properly protect this Toyota Corolla.

I will then explain the differences between the different undercoats and what you should expect from having your car undercoated. I also discuss the proven best way to undercoat your vehicle with High-Viscosity Oil Undercoating and why."

Follow along with the host in the short video below and find out:

1. Just because your vehicle was undercoated does not mean it was done correctly by some undercoating services.
2. Where to look for evidence of poor undercoating provided to your vehicle.
3. The sure sign that your vehicle was improperly undercoated you can determine in less than a minute with simple tools.
4. The expert recommendation for preventing undercarriage rusting that works best.

If you prefer, a summary of key points is provided immediately following the video.

The Shocking Truth About Toyota Corolla Undercoating

Video Summary Key Points

1. Some services do not remove the skid plates covering the engine and subframe cross members. This defeats the purpose of applying an undercoating since the spray will not reach all areas at risk of rusting.
2. Hard metal edges are typically the first place to look for the beginning signs of rust development.
3. A sure sign of improper undercoating is finding distinct undercoating spray edges where the skid plate or other undercarriage shields were not removed, preventing proper undercoating.
4. Another sign of improper undercoating is flaking or peeling undercoating on plastic skid plates and shields.
5. Failure to remove skid plates and shields is not the only problem. Often, uncovered areas are skipped due to poor spraying technique or laziness.
6. Not all undercoating products work. Some will allow rusting to occur beneath the coating.
7. No undercoating is permanent. They must be "touched up" periodically to continue working as they should.
8. Using a High-Viscosity Oil undercoating is the recommended best undercarriage protection.

Although the host does not explicitly state the product's name, from his website, it appears he uses New Hampshire Oil Undercoating NHOU® ―a non-petroleum oil with corrosion preventive additives that penetrates deep into your vehicle's metal components acting as a barrier of protection that displaces moisture and defends against corrosive elements like salt.

"Our environmentally friendly, non-petroleum oil-based products penetrate rust to reach the base metal and deep into seams and body cavities, creating a robust barrier against the elements," states the host's website.

One Bad Idea Undercoating Alternative

Multiple car forum discussions about DIY undercoating will occasionally recommend spraying old used motor oil underneath a vehicle as an effective way to inhibit water and road salt exposure for winter protection. For example, "How often do you see rust around the area of the oil plug?" as a rationale presumably provided as supporting the efficacy and wisdom of this suggestion.

However, it's a bad idea―on multiple levels.

The least is that used motor oil may eat through rubber components under your car, creating another problem.

But What About Using Rubberized Undercoating Instead?

Rubberized undercoating is fraught with at least one fatal flaw when it comes to protecting your vehicle from rust: If a crack develops (which it eventually will) anywhere in the coating, moisture can accumulate and spread between the rubber coating and the metal frame, resulting in hidden rust that will eat through the frame without you even knowing it is happening until it becomes obvious or something gives on your car or truck.

According to a South Main Auto LLC YouTube video that addresses the question of using a rubberized undercoating:

"In our experience here in the salt belt, this type of rubberized undercoating WILL DESTROY your vehicle," states the host as he showcases a Chevy Silverado with his prognosis, "Unfortunately, this vehicle will not make it past ten years old before the frame is completely rotted in half, despite the customer doing what he thought was right."

More specifically, the host is primarily referring to a particular popular brand and had this to say about it and the problems it causes:

Used Car Warning Regarding Rust

When is it patina, and when is it rust? This is an important distinction as one used car owner recently discovered stating that:

"The mechanic after looking underneath my car immediately came to me saying this car should never have been sold."

Let Us Know Your Thoughts and Experiences with Car Undercoating

Do you undercoat your car, or have you done so in the past? Did it work or fail? What would you recommend that the Toyota owner do at this point after a sloppy undercoating job was discovered?

Timothy Boyer is an automotive reporter based in Cincinnati who currently researches and works on restoring older vehicles with engine modifications for improved performance. He also reports on modern cars (including EVs) with a focus on DIY mechanics, buying and using tools, and other related topical automotive repair news. Follow Tim on Twitter at @TimBoyerWrites as well as on Facebook and his automotive blog "Zen and the Art of DIY Car Repair" for useful daily news and topics related to new and used cars and trucks.

COMING UP NEXT: I Just Had My Toyota 2024 Prime In For Its First Service (5K Mile), and "They Found Mouse Fur On The Cabin Air Filter. They (Mechanics) Say It'll Cost $550" ― Can Owners DIY Fix and Prevent This Problem?

Image Source: Deposit Photos and author’s creation