Salt speeds up the electrolytic reaction that occurs between iron and oxygen in the presence of water, so a wet and salty undercarriage during the winter months is at an even higher risk of rusting out. You can help keep things free of corrosion by adding your own light covering of oil or undercoating, which will cling to the metal and repel water.
Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.
If rust gets into a vehicle’s frame or body structure, it can become a safety issue for drivers. In fact, if a vehicle’s structure gets rusty enough, there could be a catastrophic failure even in routine daily driving.
First, moisture and carbon dioxide in the air mix to create a weak acid that starts to dissolve the iron. Think about how easy it is to crumble a flake of rust between your fingers, and then imagine that stuff trying to protect you and your loved ones during a car crash.
A stray piece of gravel or a minor fender bender is all it takes to chip a car ’s paint, and any iron in the body panels will start to rust as soon as air and water reach the metal beneath it. That means rust spots can be fairly common on used vehicles, particularly if they’ve been driven in a northern U.S. state that uses chemicals and salt to device winter roads.
But if the rusting process goes on too long, it can eat right through the metal, causing holes and allowing body panels to fall to pieces. This is where problems go from cosmetic to dangerous, because modern cars and SUVs rely on these body panels for their structural integrity.
The most serious problems occur when rust gets beneath the car ’s surface and within its underlying components. Rust -free body panels boost a vehicle’s structural integrity, but the parts doing the heavy lifting lie under the car ’s skin.
Unfortunately, this area of a vehicle is often susceptible to rust -causing chemicals and water, which can accumulate there when a car drives down wet or icy roads. Most customers should avoid used vehicles that show strong signs of structural rust.
CARFAX also recommends getting an expert inspection that includes putting the vehicle up on a lift, to give your mechanic a better view of under body components. You can apply touch-up paint to stone chips, small scratches, and other minor nicks and dings, but truly repairing rust can take several steps, a variety of tools and materials, and quite a bit of skill.
Depending on the size and severity of the rust, blending the repaired area with the surrounding paint may require wet sanding or buffing the surface. Dirt can retain and trap moisture, and road salt, bird droppings, and other corrosive materials will eat away at paint if they’re left unattended on metal surfaces for long periods.
Waxing it on a regular basis (twice or more each year) will add a protective surface to the paint and clear coat. Wash and wax more frequently if you live near an ocean or in an area where highway crews spread salt on the roads to melt snow and ice during the winter.
Also, frequently check the fender liners and other areas under the hood, along the sides of the engine bay, for any standing water. Check the trunk or cargo area to make sure water isn’t seeping past the seals.
And it’s not just the structure; rust can corrode various parts, rendering them useless unless completely replaced. Unfortunately, rust issues aren’t confined to cars from one certain manufacturer or age group.
One major determinant of a car ’s likelihood for rusting is its geographical location. Rust problems are more common in humid climates and in areas where road crews use salt to keep ice off the streets during the winter.
Areas such as the Upper Midwest and parts of the Northeast are especially known for rusting vehicles, largely because they suffer from both humidity and heavy road-salt use. But just because you’re located in an area that isn’t known for humidity or salt use doesn’t mean you’re safe from rust.
Common rust spots include the frame rails, which run underneath a car ’s doors on each side, the wheel wells, the exhaust, the suspension and virtually any other underside components made of steel or metal. Once you have the car back on the ground, pull up the trunk carpeting and check for any signs of rust.
While we generally suggest consulting a professional about these issues, you can usually remove rust spots by sanding them away, so they don’t become worse and create further problems with your car. I spotted some rust on the underside of the car between the back wheels.
By the time the inspection was completed (and failed), I had a hole in my muffler system along with about $2,500 worth of rust related repairs for a $1000 vehicle. However, to check you're going to have to do the squeeze test between fingers and thumb on the thicker structural sections, then if you still can't determine how severe or not the rust is. It's time to get an old screwdriver out and tap (with the handle part) on the rustiest bits.
If the material is corroded right through holes will likely appear, this is not good especially in the structural sections, if this is the case then you may like to walk away from this one as welding will be required. If however it is just surface rust then a scrap off and clean up followed by an application of under body protection will suffice and your good to go.
The seller should have no issues at all with you taping on the structural parts of the body to check its integrity. In some parts of the world where lots of salt is used in the winter, this is not unusual rust.
If you want to keep it longer term, I'd treat the rusty areas on the under body with a wire wheel brush on an angle grinder, rust converter and fresh undercoating after a thorough clean. “Besides the obvious body corrosion, the under carriage is totally exposed to the elements, so it can affect your exhaust system, your suspension,” he said.
Meteorologist Lindsey Slater's husband, another mechanic, said that's especially important for drivers who park in a heated garage. Some collision shops offer a spray for a car ’s under carriage that can help prevent rust.
Microsoft may earn an Affiliate Commission if you purchase something through recommended links in this article. Rust is a problem for many car owners, and it can damage many of your vehicle’s components, including the body, engine, and electrical equipment.
These simple but effective products create a protective film that prevents metal from rusting. Shield’s anti-corrosion spray was developed by the Boeing Company to lubricate and protect aircraft components.
The liquid is formulated to restore and extend the life of metal surfaces with ease by converting rust into chemically stable iron mandate. In addition, it’s simple to apply using whatever method suits you best, such as by brush, roller, or spray.
The no-run solution makes it easy to apply, whether you’re protecting a car, truck, or recreational vehicle. Another great feature of this spray is that, when you apply it correctly, the layer of rust protection also acts to absorb and deaden road noise.
This corrosion inhibitor provides a tough but flexible coating that’s suitable for a huge range of metal components. The spray is easy to apply, and its carefully blended formula is designed to creep into every nook and cranny before firming up to provide a durable layer of protection. Suitable for marine use as well as automotive applications, CRC’s rust -proofing solution will hold its own even in wet, salty conditions.
CRC recommends using its product on everything from electrical connections to engine components and trailers. Users report that this spray provides a thinner, more even coating than many of its competitors.
The formula can be safely applied not only to metal but also to body filler and fiberglass, making it one of the most diverse options on the market. A number of people have used this product to salvage metal that would otherwise have gone to the scrap heap, making it a great option for thrifty hobbyists. The formula easily dries to a highly flexible and shatterproof layer, which prevents further rust from forming.
Users report that the formula really grips to rust and is easy to apply, making it ideal for the underside of any vehicle. Because the coating easily spreads out to a thin and even layer, it also goes a lot further than you might expect. With just an inexpensive bristle brush, whole vehicle undersides can be covered with a single can.
The result is a smooth layer that stands up against chips and scratches. Another unique feature of the formula is its UV resistance: powerful radiation from the sun won’t damage the coating. This makes it the perfect option for use in all climates, whether you need to protect your car from snow and salted roads or the blazing sun.
Permeated’s solution is a true rust killer, dissolving rusty spots in mere minutes and leaving behind a durable polymer coating. Easy to apply by brush or spray, the coating makes an excellent rust -proof primer that can be easily painted over to ensure a durable finish. The formula is suitable to use with body filler and fiberglass as well as metal, making it a diverse solution for most automotive surfaces.
Users report that Permeated’s formula is highly effective and easy to apply, making it a handy bottle to keep on hand around the garage. The solution instantly converts rust to an inert surface that can then be painted over for a smooth and durable finish that resists the formation of rust in the future. In its cleverly designed bottle, the solution can be sprayed at any angle, making it easy and comfortable to apply no matter what part of your vehicle needs to be treated.
Great solution for salvaging rusty metal parts that might otherwise be abandoned With this in mind, it should come as no surprise that deciding on exactly the right solution for your needs can be a challenging task.
When choosing a rust prevention treatment, one of the first things to check up on is what type of surface the product is suitable for use with. Plenty of rust prevention and vehicle undercoating solutions are suitable for use on fiberglass and body filler as well as metals, but this is not always the case.
Another key factor that will influence your decision is whether you want to deal with existing rust, or simply prevent it from forming in the future. Most of the solutions on this list perform both functions, but it’s always a good idea to double-check.
If you are planning to treat a visible surface, make sure you choose a rust inhibitor that can also act as a primer, so you can easily paint over it. Bear in mind that products designed to convert existing rust tend to leave a dark brown or black surface behind, so you will probably need to apply at least two or three layers of paint to adequately cover it.
If you dislike the idea of working your way over multiple uneven surfaces with a wire brush, you may wish to choose a rust inhibitor that can be applied via spraying. Rust proofing cars are one of the single best ways to keep vehicles in the best possible condition.
Corroded components are more likely to fail over time, and could be costly and difficult to fix. Because of this, rust proofing your car is a small investment that makes for huge benefits further down the road (pun not intended).
Before paint is applied, car bodies are typically treated with what is known as an undercoating, which is designed to protect the vehicle against damage. They protect a vehicle’s undercarriage against dust, moisture, and dents, as well as helping to reduce road noise.
This polymer coating tends to be quicker and easier to apply than its rubberized counterpart. The undercoating seeps into any cracks and seams, and bonds with non-rusty areas to protect it against corrosion.
Applying this type of undercoat is typically more time-consuming, as it takes longer to cure than wax, polyurethane, or rubberized undercoatings. As mentioned earlier, you will need to decide whether to use a spray or paint method when the time comes to rustproof your vehicle.
This is because iron is a relatively reactive metal, which can form chemical bonds with a number of elements. A: Applying a rust -proof undercoating at home is a relatively straightforward endeavor, which most keen automotive DIY enthusiasts can undertake.
It’s also a good idea to wear a dust mask or ventilator and work on a day with low humidity to ensure the coating dries as quickly as possible. For a whole car body, you’ll usually need to strip the existing paint away to apply a rust -proof undercoating, whereas to treat the undercarriage will usually mean a simple wash.
In just one step, the spray dissolves minor rusted areas, displaces dirt and grime, provides lubrication for moving parts, and dries to a tough yet flexible anti- rust coating.