5 Prime Areas to Look for Rust

Rust. It’s everywhere. Okay, maybe not everywhere, but it’s the stuff of nightmares for the general daily driver to the full-blown gearhead. And for most people living in the United States, it’s a regularly occurring issue. While many mechanical components require relatively easy rust repair, body panels are another story. And make no mistake—unchecked rust problems will destroy the body and chassis of the car quite rapidly. Regularly inspecting your vehicle for rust should be a routine task, as we’ve discussed in previous articles on this topic. It’s also an absolute MUST when considering purchasing a used vehicle. No one wants to make the costly mistake of purchasing a problem child! Don’t set yourself up for failure this winter season. Here are the top five areas you should be checking for rust.


According to a 2017 AAA survey, “U.S. drivers paid an estimated $15.4 billion in rust repairs caused by de-icing methods over the last five years, or approximately $3 billion annually. AAA warns drivers, especially the 70% (150 million) who live in areas affected by snow and ice, to take action to prevent dangerous rust-related vehicle damage.” This is one situation where you really don’t want to follow the pack!

When checking for rust, a good place to start are the rocker panels. Rockers catch a lot of debris from the road that chip away at the paint. They’re also on the front line of the nasty chemicals and other corrosive elements used on the roads that can cause rust—like those pesky de-icers. Because of this, you want to make sure that your rocker panels are in sound shape.

If you find any exposed bare metal or early signs of rust, you want to address the issue immediately. Clean away any rust, paint over bare metal, and perform proper path panel repairs if necessary. On average, you can expect to pay at least $1,000 to have a body shop repair rocker panels. That’s why addressing the issue before it spreads further is well worth the investment. Besides, passing your state inspection relies on it.

If you are shopping for a vehicle, then checking for sloppy repairs is just as important as checking for rust. Some dishonest dealers have found that filling rust holes with foam and then shaping and finishing it can hide problem areas. Knock on the panels and look closely for any hints that the area has been treated for rust or rot.

Wheel Arches

Wheel arches are another common area that experience rot. When inspecting for rust, look for any bubbles forming in the paint and run your hand along the surface—you’ll be able to physically feel the rust starting on the other side. Preventing rot in this area is difficult because manufacturers tend to use very thin metal in wheel arches. Undercoating helps, but almost every vehicle will need this area professionally repaired when serious rust forms. Doing it yourself can cost a few hundred dollars but at the shop you can expect to drop about $1000 per side.

When shopping, be sure to really analyze this area for rust. Again, dishonest sellers may use fender flares to hide rust on wheel arches. On a Dodge I purchased a few years ago, I foolishly neglected to inspect this area thoroughly. Less than a year later, I found the area was packed with body filler and rotted away. If I had used a magnet to test the surface area, I would have prevented myself from investing in a project vehicle I didn’t need.

Lower Rear Quarter Panels

This is another area that is important to focus on when checking for rust. Almost always a problem on older vehicles, quarter panels experience many of the same harsh conditions as rocker panels. Check this area often on your own car—especially if you live in an area with harsh weather conditions and chemically-treated roads. If the area isn’t protected by any sort of undercarriage shielding, you will want to physically feel the area behind the panel. Quarter panel replacement will likely run at least $2000 for full replacement on either side. Identifying and addressing it early can save you thousands in repair costs.

Rust in this area is hard to hide, but Bondo filler works magic for many. Physically knocking on the area and listening for pitch changes will tell you whether or not rust is hiding on a vehicle you are considering buying. Also, if a piece of steel is riveted over the rust in this area you can bet your bottom dollar the issues underneath are quite severe.

Floor Pans

Carpets, insulation, and a variety of mechanical components can obstruct viewing abilities when checking for rust on floor pans. But they often experience rot and when this happens, things can become uncomfortable or even dangerous. As a kid, my father’s F-150 had floor pans rotted out so bad that I almost dropped a CD right onto the road as we were driving. If you find that your floorboards are rotted, you again can be facing thousands of dollars in repairs. Properly inspecting your vehicle for rust in this area can save you money—and your mixed tape!

When browsing used vehicles, checking for rust on floor pans will require some flexibility. You’ll need to crawl underneath the car and use a light to search. Small pinholes and light surface rust may be hard to pinpoint but are worth spotting. And if you get under there and find a stop sign riveted to the floor, it’s a good sign to stay away or get to work.

Frame Rails

The frame of a vehicle is generally constructed from lower gauge steel. This means that it will stay structurally sound longer than thinner components. However, it’s still subject to rusting. And when a frame begins to rot, the cost of repairs can actually outnumber the value of the vehicle, so checking for rust in this area is imperative. In addition to a visual inspection, knocking and listening for pitch changes will also tell you how far gone the metal is.

Unibodies are very common in vehicles today and can rust out just as quickly as body panels. The subframes are made from thinner materials and if they are exposed to the elements they’ll rot up in no time. Whether unibody or full frame, checking for rust is the same process. Frame rails run along the perimeter of the vehicle under the car’s doors so once again, grab that flashlight and take a look under the belly. If the frame or subframes are rusted severely, you will want to stay away from the car unless you’re ready for a massive project.

Investing in rust repair is something nobody wants to deal with, but it’s something we inevitably have to face—especially if you live in the colder regions of the world. Assessing the damage and properly fixing the problem will not only give you peace of mind, but also open the door to practice body repair and build new skills. Remember, every challenge is an opportunity to grow and that’s what this industry is all about.

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