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With no undercoating to protect it, a brand-new 2025 Chevy Colorado ZR2 birthday gift is raising questions and concerns among truck owners.
Brian Luhtala on the Chevy Colorado/Silverado truck owners Facebook group says,
“I put the steps on my wife’s birthday present tonight, a 2025 Chevy Colorado ZR2, and noticed there’s no undercoating. Am I missing something? Is thing not a thing anymore? Guess I should take a look under our 1 ton.”
Is Undercoating a Thing Anymore?
Brian’s question gets to the heart of a major change in the automotive industry. When he looked under his wife’s new 2025 Chevy Colorado ZR2 and saw what seemed like a bare frame, what he witnessed was a deliberate decision by the manufacturer. The short answer to your question, “Is this not a thing anymore?”, is: yes and no.
In the past, many vehicles came with a thick, rubberized undercoating applied at the factory. This was designed to be a physical barrier against rust, salt, and debris. However, automakers have shifted away from this approach for several key reasons, primarily due to advancements in materials and manufacturing processes.
They’ve replaced the traditional approach with modern solutions, including galvanized and zinc-plated steel, corrosion-resistant paints, and e-coatings. The goal is to build a frame that is inherently more resistant to rust from the inside out, rather than simply covering it with a thick, often problematic layer.
Rust Resistant, Not Rust Proof
This is also why you often see things like plastic wheel liners and more composite materials in modern truck beds and bodies. They’re designed to be rustproof, not just rust-resistant.
However, those who live in the Rust Belt know all too well that these factory-applied coatings can and do fail. I’ve seen countless examples of premature frame rust on modern GM trucks, including Silverados and Colorados. Despite the advancements, road salt and de-icing chemicals are more corrosive than ever, and they find a way into every seam, crevice, and weld point.
This is why the question of whether new trucks need undercoating is more relevant now than ever. The factory protection is a good starting point, but it’s not a complete, bulletproof solution, especially if you plan on keeping your truck for the long haul.
Undercoating vs. Rustproofing: What’s the Difference?
Before we get into the solutions, let’s clarify the terminology, because it’s a common point of confusion. The terms “undercoating” and “rustproofing” are often used interchangeably, but they refer to two distinct types of protection.
Undercoating is a thick barrier applied to the vehicle’s underside, including the frame, floorboards, and wheel wells. Its primary purpose is to protect against physical damage from rocks and debris and to provide a durable shield against road salt and moisture. Common undercoating materials include asphalt, rubberized compounds, or even a hardened wax.
Rustproofing is primarily concerned with protecting the vehicle’s hidden, internal cavities. This involves spraying a penetrating oil or waxy fluid into the frame rails, door panels, and other seams where moisture can collect and cause corrosion from the inside out. This type of coating is designed to displace moisture and prevent oxygen from reaching the metal.
For the ultimate protection, you really need a combination of both. The undercoating protects the exterior surfaces, while the rustproofing protects the internal, hard-to-reach areas.
So, now, what’s the solution? You have two primary options for approaching this.
Option 1: The DIY Approach
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If you’re comfortable getting your hands dirty and have the right tools, this can be a cost-effective way to complete the job. The key here is proper preparation. You’ll need to thoroughly wash and dry the underside of the truck to ensure it’s free of dirt, debris, and any moisture. A pressure washer and degreaser are your best friends in this situation.
For the DIY job, the recommendation is a penetrating oil-based undercoating. This is often regarded as the best rust prevention for a truck frame because it not only creates a barrier, but also soaks into seams and spot welds, displacing any existing moisture and preventing rust from ever taking hold. It also has a “self-healing” property, meaning if a rock chip or scrape occurs, the oil will creep back in to reseal the area.
A good example of this is a lanolin-based product. It doesn’t harden, so it won’t crack and trap moisture like some rubberized coatings can, which is a key point in preventing future problems. Be sure to spray it liberally inside the frame rails and other cavities.
Option 2: Professional Application
For peace of mind and a job well done, a professional application is often the best choice. While it’s more expensive, the technicians have the right equipment to reach every nook and cranny. When you take your ZR2 in, ask them about a two-part system. The first part should be a penetrating oil or wax applied to all the inner cavities, and the second part should be a durable undercoating applied to the exterior of the frame. This dual-layer approach offers the most effective protection against corrosion.
When researching shops, be sure to find one that uses a reputable product and has experience with modern truck frames. Look for reviews that specifically mention their work on late-model GM trucks to avoid common Chevy Colorado undercoating problems from improper application.
What’s Happening Underneath Your Truck
The issue is often not about a lack of coating, but rather the type of coating. The factory coatings can be thin and brittle. They’re designed to protect against a certain level of exposure, but in severe climates with heavy road salt, they aren’t up to the task.
What Brian observed is that the 2025 Chevy Colorado ZR2 has a very clean, seemingly “bare” frame. This is actually good because it means there’s no pre-existing rust. It’s a pristine canvas for applying the best undercoating for a new truck—a process that will ensure the frame remains solid and strong for decades to come.
Taking action now, before winter hits.
The investment will more than pay for itself in the long run by preserving your truck’s value and preventing costly, extensive repairs down the line. I’ve seen frames so rotted they become a safety hazard, and a simple aftermarket undercoating could have prevented it.
Conclusion:
The market for 2025 Chevy Colorado undercoating options is extensive, offering a wide range of choices.
Just remember to prioritize a quality product and a thorough application process. Whether you opt for a professional or a DIY kit, the most important thing is that the application is done on a clean, dry surface and that you cover all the hidden areas.
Brian’s wife’s new ZR2 is a beautiful and capable machine, and taking this step will ensure it looks just as good underneath as it does on the outside for years to come. Don’t forget to take a look at your 1-ton as well; the same principles apply.
It all boils down to this: taking a proactive step now will give you peace of mind and protect a valuable asset. The factory does a good job, but they don’t account for every scenario and every environment. A little extra care now goes a very long way.
How About You?
Have you experienced rust on your new GM truck, and if so, what did you do about it? Have you used an aftermarket undercoating? Let me know in the red Add New Comment link below.
Check out my 2024 Chevy Silverado story: My 2024 Chevy Silverado Is Rusting Through the Frame After 16K Miles, My Ram With 100K Was Nowhere Near This Bad
I am Denis Flierl, a Senior Torque News Reporter since 2012. My 30+ year tenure in the automotive industry, initially in a consulting role with every major car brand and later as a freelance journalist test-driving new vehicles, has equipped me with a wealth of knowledge. I specialize in reporting the latest automotive news, covering owner stories, and providing expert analysis, ensuring that you are always well-informed and up-to-date. Follow me on X @DenisFlierl, @WorldsCoolestRides, Facebook, and Instagram
Photo credit: Denis Flierl via Brian Luhtala
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Source: torquenews.com
