Underbody Cleaning: The Essential Guide | Autance

Very few car owners pay attention to the undercarriage of their automobiles. After all, this is a part of the…

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Underbody Cleaning: The Essential Guide | Autance © Underbody Cleaning: The Essential Guide | Autance

Very few car owners pay attention to the undercarriage of their automobiles. After all, this is a part of the vehicle that no other person in his right mind will want to look at. However, this doesn’t mean you shouldn’t take good care of your undercarriage anymore. For starters, it is the platform upon which all the other components of your vehicle rest on. It serves to protect these components from premature wear and deterioration. As such, it is imperative to clean the underbody of your car once in a while.

Why Clean the Undercarriage

There are many reasons why you should clean your car’s undercarriage. First and foremost, there’s plenty of dirt, dust, and road grime that may have already accumulated in this part of the car. Every time you drive, smoke, dust, dirt, and other particles can get blown into the underside of the car. Since this is not often included during regular car washes, these particles can accumulate over time. If you’re going to run your fingers on one section of the underside, you’ll get a thick muck of grime.

For those living in colder climates, road salt can be sinister. Salt is often caked on the snowy or icy road. The problem here is that salt can speed up oxidation. Salt reacts with oxygen present in water and the metal components of the car’s underbody. This leads to the formation of metal oxides. Among car owners, one metal oxide is a real concern – iron oxide or rust. Rusting metal components can bring about different problems in your car. For the most part, rust can damage the integrity of the car.

The other issue with salt is that it also serves as a hygroscopic molecule. It attracts water molecules such that it keeps on fueling the oxidation reaction. This is why it’s important to remove salt that’s caked onto your car’s underside.

For individuals living in warmer climates, they may not worry too much about road salt. However, those driving near the sea or ocean are also subjected to the same effects of salt on their vehicles. The salt, in this case, may not be present on the road. But, it sure is present in the air. Hence, rusting is still a very possible scenario.

Now, if you’re into showing off your ride, then having a clean underside helps, too. After all, you don’t get to drive to a motor show with your car looking pristine on the topside, but all grimy and dirty on the underside.

In short, cleaning the underbody of your car is as important as cleaning the rest of it. If you can devote a fair amount of time cleaning and detailing the body of your car, then you should also employ the same dedication to its underside. It makes sense.

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Tools and Materials You’ll Need to Clean the Undercarriage

Now that we know why we need to clean the underbody of our car, let’s get down to it. The first thing you’ll need is to gather all the supplies, tools, and materials you’ll need to clean the underbody. Here’s a list of tools that you may need.

  • Pressure Washer

Without a doubt, a pressure washer is the single most important piece of tool that can help you clean the underbody. The powerful jet of water can blast away dirt and grime much easier than a conventional water hose. Most pressure washers come with an extra-long nozzle attachment, so you can clean hard-to-reach areas.

  • Air Compressor

After washing and cleaning, it is important to dry the underbody very well. If not, you’re still courting corrosion to set in. Unfortunately, drying crevices and tight spots can be very difficult. An air compressor can blast water beads off and help dry the surfaces.

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  • Steam Cleaner

While not an absolute essential, it will be great if you also have a steam cleaner. This is perfect for loosening up oily deposits in the undercarriage. The heat coming from the steam can “liquefy” caked-on grime, so that it is easier to remove.

  • Brushes

You’ll need both stiff- and soft-bristled brushes. You may also need brushes that come with smaller heads and longer handles. These will come in handy when working on tight or hard-to-reach areas.

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  • Polisher

It is not necessary that you have a polisher with you. However, if you’re also pondering on cleaning the exhaust system, a polisher can give it a good finish.

Here are some materials that can help you in cleaning the undercarriage.

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  • Degreaser

This is perfect for removing water-insoluble compounds or substances like grease, abrasive dust, lubricants, and others. It’s the perfect cleaning aid to keep your car’s underbody in pristine condition.

  • All-purpose Cleaner

You may also need an all-purpose cleaner to remove grime and dirt in general. This is a worthy product to have in lieu of a degreaser.

  • Metal Polish

This is for cleaning your exhaust and other components that may have already lost their shine. It’s also ideal for oxidized and dull parts.

  • Traffic Film Remover

This removes the very fine layer of oils, dust, and grime from the underbody of the car. It’s a solvent-based formulation that can come in different types.

  • Fallout Remover

Fallout removers are helpful in decontaminating the surface of the underbody. It does not mechanically-remove iron oxides or rust. What it does is that it creates a chemical reaction to remove the particles of iron oxide from metal surfaces.

  • Steel Wool

If you notice surface contaminants on metal surfaces, it’s always a good idea to use Grade 000 steel wool. This acts like an abrasive that eats away at stubborn contaminants on very hard surfaces.

  • Tar Remover

It is inadvertent that tar may accumulate on the underbody of the car. This is true for those who drive on asphalt roads as well as construction sites and industrial establishments. Tar removers can remove such nasty residues on the underbody. These products are also excellent for removing caked-on glue.

Cleaning the Underbody of Your Car

Cleaning a car’s undercarriage can be tricky. If you have a vehicle that has a high ground clearance, then getting under the car should be easy. For most vehicle owners, however, cleaning the underbody often means lifting the car. This can include lifting the car with hydraulic jacks and setting it on jack stands. The wheels are also removed to allow for better access of the undercarriage. For a more thorough cleaning, some folks will employ a mechanical lift that will raise the vehicle several feet off the ground. This allows for better visualization of problem areas. It also ensures better movement during the cleaning process.

Always wear the appropriate safety gear whenever you’re working on the underbody of a car. Goggles are a must as you’ll be spraying the undercarriage. Debris and grime may splatter all over you. Gloves are also required, especially if you’re going to use chemical cleaners. A face mask will also come in handy.

Start under the fender. For this, you need to remove the wheels and then cover the brake assembly with a waterproof material. You can use plastic sheeting for this. Make sure it is fully secured with a tape.

Spray water into the fender wells. Adjust the water pressure to the highest possible setting. Start at the front section of the wheel arch, then work your way towards the rear. Do it one section at a time. You should see dirty water streaming down from the wheel arch. Stay in this location until you see the water turning clear. Repeat the same action in other sections.

Proceed to cleaning the rest of the underbody. Again, it is best to work in sections, so you can cover everything.

If you notice a heavy coating of grime or oil, get your degreaser or traffic film remover. Spray or apply the substance over the problematic areas. Let the formulation work its way through the grime. After a few minutes, give it a good spraying with your pressure washer.

The same is true for other products. For example, if you notice severe fallout or metal oxidation issues on the underside of the car, then you can use a fallout remover. The thing to remember here is to allow these products to apply their effects first before rinsing.

Once you’re done cleaning, it may be wise to follow it up with an appropriate foaming product. This will penetrate awkward areas that are otherwise difficult to reach. This can also help remove other debris that may be left on the underbody. Again, let it stay on the surface for a while before you rinse it off.

The final rinse should remove any leftover particles or residue on the undercarriage. If you see the water returning with particles, don’t let up. Keep on spraying until the water return is clear and clean. Now get your air compressor and remove water from crevices and tight spots. Make sure to dry the undercarriage before you hit the road again.

It is okay not to clean the underbody every time you wash your car. Cleaning it once or twice a year should be enough to help maintain its surfaces.


  1. Proper Maintenance of a Vehicle’s Undercarriage, Dr. Beasley’s
  2. Underbody Cleaning, Car Cleaning Guru
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