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corroded undercarriage of a truck due to salt and winter weather

It might be warm right now, but winter is around the corner. After living in southern California for the past decade, I'd sorta forgotten about the beating that cars up north take due to salt and other chemicals used to keep the roads safe to drive on during winter storms. As good as these are to get rid of ice ... they are equally good at damaging trucks, SUVs, and cars. That means that you need to do something to shield your truck from the damaging effects of road salt corrosion. Sure, I'd already planned to wash my undercarriage regularly and I'd thought about applying protective coatings last winter but it seemed like overkill. Last week, though, I was talking with a friend who's lived in Ohio all his life, and he shared some efficient and effective ways that he uses to keep his truck going strong. Here's what he shared about maintaining a vehicle's body condition throughout the colder months and some mistakes he made that we can avoid!




Understanding Salt's Corrosive Effects

To fully understand the need for applying protective coatings and other actions such as regular washes, it is essential to understand the damaging effects of salt on your truck. While those expenses might seem unessessary, in comparison to the money you can save by preventing costly repairs this is an obvious choice. Additionally, it isn't just about the cosmetic look of your truck - though nobody loves seeing rust holes and parts falling off - it's also about ensuring optimal performance and safety during winter.

When salt-laden slush splashes onto the undercarriage, it can corrode and weaken metal parts, posing a significant threat to your brake and exhaust systems. This corrosion can impact your truck's performance and safety, making it crucial to address the issue promptly. In the US alone, over $5 billion is spent annually on repairing salt-related damage to vehicles, underscoring the severity of this problem.

Individually, that number can range from as low as $200 for a simple spot of rust damage to as much as several thousand dollars for truck body repair that has developed over several years and affected multiple parts of a truck. Again though, that number is specifically for body damage. In our case, the severe rust damage has led to electrical failures, suspension parts failing due to the mounting brackets rusting through and breaking off, as well as other issues related to wires and hoses where mounting points became loose.

Salt, specifically sodium chloride (NaCl), is notoriously damaging to truck bodies and other vehicles, particularly in regions that use road salt to manage ice and snow. Here’s why salt is bad for truck bodies and how it attacks metal:

Corrosion Acceleration

Salt acts as an electrolyte, which can significantly accelerate the chemical reaction of corrosion (also known as rusting) on metal surfaces. This happens because salt water conducts electricity better than pure water, which facilitates the movement of electrons between metal and oxygen in the presence of water. This electron movement is a key part of the corrosion process.

Moisture Retention

Salt has hygroscopic properties, meaning it attracts and retains moisture from the environment. Even in conditions where there would normally be no liquid water (like in cold, seemingly dry conditions), salt can attract enough moisture to form a saline solution that continues to facilitate corrosion.

Lowering the Freezing Point of Water

By lowering the freezing point of water, salt ensures that metal surfaces remain wet for longer periods, even in freezing temperatures. This persistent moisture presence increases the duration during which corrosion can occur.

Formation of Rust

When iron (a major component of steel used in truck bodies) corrodes, it forms iron oxide, or rust. Rust is not only aesthetically unappealing but also structurally damaging, as it is more brittle and weaker than the original metal. Over time, rust can significantly degrade the structural integrity of a truck body.

Pitting Corrosion

Salt can also lead to pitting corrosion, a localized form of corrosion that leads to the creation of small holes in the metal. These pits are particularly dangerous because they can lead to structural failures if they occur in critical components of the truck body.

To mitigate these issues, it's crucial to regularly wash vehicles during and after the winter months to remove salt deposits, and if possible, apply protective coatings that can help shield metal surfaces from direct exposure to salts.


Salt Alternatives For Winter Roads

During the winter months, various alternative chemical solutions beyond salt are being explored as alternatives that offer better environmental safety and reduced damage to cars, trucks, and roadways. While these are effective at keeping roads safer, many can still cause damage to vehicles. Here are some commonly used road chemicals besides salt that can harm your truck.

ChemicalLevel of Vehicle DamageDescription
Sodium Chloride (Salt) Moderate to High Standard road salt, effective at melting ice but highly corrosive to metal parts.
Calcium Chloride High Absorbs moisture from the environment, works at lower temperatures, but more corrosive than salt.
Magnesium Chloride High Effective at very low temperatures and is hygroscopic, leading to prolonged metal corrosion.
Calcium Magnesium Acetate (CMA) Low to Moderate Less corrosive alternative that prevents ice from bonding to the road, safer for the environment.
Potassium Acetate Moderate Used mainly at airports, it is less corrosive than chlorides but still can oxidize metal over time.
Urea Low Less corrosive fertilizer used as a deicer, particularly near water bodies due to lower toxicity.
Beet Juice and Cheese Brine Low Organic, mixed with salts to reduce chloride use, environmentally friendly but can promote microbial growth.
Glycerol Based Deicers Low Newer, less corrosive, mixed with other chemicals to enhance effectiveness, environmentally friendly.

No matter what chemical is used to improve road safety during winter, protecting your truck should always involve regular cleaning during the winter months. Personally, this is why I invested in a monthly pass at a local car wash so that I could budget better and not have to debate the value of spending an extra $5 or $10 each time I wanted to rinse the road grime off. 

Protect Your Truck This Winter with Protective Coatings

To shield your truck from the winter elements, my neighbor strongly encouraged me to apply protective coatings like ceramic coating or paint protection films. Bed liners and coatings like Durabak act as a tough armor against salt corrosion, enhancing your truck's durability and aesthetic appeal. While typically designed for protecting the truck bed from scratches, they can also be sprayed onto the bottom of your truck to protect from undercarriage damage.

Ceramic coating are another option that offers a glossy finish and provides water repellency, UV resistance, and chemical protection. However, this is not going to protect your undercarriage - though it makes getting the salt and road grime off of the top of your truck easier so that you can keep your truck in top condition even in the toughest winter conditions.

An alternative to ceramic is waxing. This simple maintenance step creates a protective barrier against contaminants and boosts your truck's appearance. While typically we think of wax as a paint protector that aids in keeping the paint from attracting dirt, there are products such as Hard-On by WooWax that can be applied that will act as a hard shell that covers your entire vehicle. These are not perminant solutions but will typically last 5-10 years before needing to have it removed and reapplied.

There are plenty of great options for DIY guys that want to prevent rust, but if you are like me and don't have the tools, time, or knowledge - companies like Ziebart can help with a professionally applied rust protection coating. 

No matter what your choice is, protective coatings are the best choice when it comes to protecting your truck from rust. The simple reason is that they all put a barrier between your truck's metal body and the corrosive road chemicals while also sealing the vehicle from water which on its own can be a brutal beast that attacks metal truck bodies.

Winter Truck Storage to Prevent Salt Corrosion and Extend Vehicle Life

While it is impossible to hide your truck away from the elements, you can protect it when you aren't on the road by parking in a garage and making sure to clear snow away from the vehicle instead of parking it in a snowbank or allowing drifting snow to collect around the truck.

Storing in the Garage

The best protection you can offer your truck during winter is to park it in a garage. This not only shields it from snow, ice, and frost but also protects it from corrosive materials like road salts and de-icing chemicals that can splash onto your vehicle on the roads. A garage provides a stable, warmer environment, preventing the fluid and oil in your truck from becoming too viscous, which can strain the battery and engine during startup.

Using a Carport

If a garage is not available, a carport is a good alternative.

Thankfully, these days, there are lots of options designed to be robust enough to stand up to winter weather while also being able to be taken down in the warmer months. You can even find temporary car ports that allow your truck to be fully enclosed, offering similar weather protection to a garage.

Since most carports are not enclosed, they won't offer as much protection as parking in a garage. However, a carport can still shield your truck from direct snowfall and reduce snow and ice accumulation on the vehicle. This partial enclosure can help minimize the exposure to moisture that could lead to rust and corrosion, particularly under the vehicle and around the brakes and wheels.

Keeping It Free from Snow Build-Up In The Driveway

While temporary winter carports are a great option for people who lack a garage, not everyone has the space to do this and plus, you still need to protect your vehicle even when visiting others.

So, when you can't park the truck inside, make sure to clear snow from around your truck, especially around critical areas like the wheels and exhaust pipes. Snow packed around the wheels can freeze and harden, potentially interfering with the braking system and making it difficult to drive the vehicle safely. Snow blocking the exhaust can cause dangerous gases to back up into the cabin or even stall the engine. Ensuring that these areas are free of snow helps maintain the operational integrity of your truck and prevents rust and corrosion.

Implementing these strategies will not only extend the life of your truck but also ensure it remains safe and reliable throughout the winter months.

Winter Can Be Beast But You Can Fight Back

Winter can be a brutal beast but there are ways that you can fight back. Since water and corrosive chemicals are the enemy here, your first priority is to do what you can to prevent them from attacking your truck. Do this by a combination of beefing up your truck's armor through protective coatings and regular washings but don't forget to protect it at home as well by keeping it free from snow and ice in your driveway.

Corrosion from winter road chemicals is almost avoidable but these tips should help extend the life of your vehicle, at least that's what my neighbor tells me. we'll find out I guess!