How To Protect The Undercarriage From Salt


In the winter, many cities use salt to help melt ice and snow on the roads. However, salt can also cause damage to the undercarriage of a car. Over time, salt can corrode metal parts, leading to rust and other problems. In addition, salt can also damage rubber and plastic components. So, how can you protect the undercarriage from salt?

In this article, I will be showing you an easy method to protect the undercarriage from salt. This will keep your car looking new for many years to come. Read on to find out more about the procedure.

To protect the undercarriage from salt you will need to park the vehicle, lift it using a jack and jack stands, remove all four wheels, wash the undercarriage, let it dry, sand down the metal parts, and apply an undercoating spray.

How To Protect The Undercarriage From Salt

How To Protect The Undercarriage From Salt

Protecting the undercarriage from salt requires putting a good solid coating on it. When the metal and plastic parts that are found underneath your vehicle have a coating on them, the salt will never reach them and it won’t corrode them. Here is how to protect the undercarriage from salt:

Note: Regardless of if you live in an area where it never snows and the city uses salt on the roads, you still need to do this. You could be living in a saltwater atmosphere (close to an ocean or sea) and salt will still get into the metal parts of your vehicle and will cause them to rust.

How Long Can You Drive With Bad Lif...
How Long Can You Drive With Bad Lifters?

1. Required materials

  • Wire brush or sandpaper
  • Professional grade undercoating spray (see prices on amazon.com)
  • Protective gear (face mask, goggles, gloves)
  • Car jack and jack stands
  • Lug wrench

2. Park the car on a leveled ground

This task will take up to five hours of work, so you have to plan things out in advance. For starters, the vehicle should be parked on leveled ground because you will need to lift the front and the back end of the vehicle to be able to get underneath the vehicle.

Also, you have to keep in mind the time required for the job. If you want to do things in one day, plan where you will be able to complete this task. If you start very early in the morning, you will probably be able to use the sunlight. However, if you are planning on starting in the afternoon, you either park the car in a garage or have some lightning source ready.

But anyways, park the vehicle on the leveled ground and make sure the parking brake is engaged.

3. Jack the front and the back end of the vehicle

Protecting the undercarriage from salt requires various tasks like washing the underside of the vehicle, sanding it, and applying the coating. This means that the vehicle should be lifted. To safely perform this task, lift both the front and the back end of the vehicle using a jack and then place jack stands for safety reasons. You can find the jacking points in the owner’s manual. Lift the vehicle high enough so you can get under it and actually work on it.

4. Remove the wheels

Removing the wheels might be a step that is adding a little bit of work for you. But, trust me, by removing the wheels you will gain so much more access and you will be able to coat a very important part of the vehicle where snow, salt, and ice sit. It is the fender. As you drive your car, the tires throw the snow behind and it just builds up on the fender. This is actually the number one area when it comes to rust damage.

In order to remove the wheels on a car, you will need to have a lug wrench in order to loosen the lug nuts. Since the vehicle is already lifted, use the lug wrench to loosen the lug nuts. Remove all the lug nuts and store them. At this point, you should be able to pull out the wheels and store them aside. Sometimes the wheels might be stuck and won’t come out immediately. Gently move them back and forth. Make sure you are not using a lot of force because your car is on jack stands and you don’t want the car to fall off the stands.

5. Wash the undercarriage

The best way to wash the undercarriage of a car is to use a pressure washer. First, be sure to lower the pressure settings on your washer, as high pressure can damage sensitive components. Next, direct the nozzle upward and move it back and forth across the underside of the car. Start from the front and work your way back. Be sure to pay special attention to any areas that are particularly dirty or likely to corrode.

However, if you do not have a pressure washer, you can use a garden hose. However, since all kinds of stuff get under the vehicle, you might also need a brush to help you remove any stubborn grime. Since you will be using a brush, you can also soak it in some soapy water. Just make sure that you rinse it very well afterward. We do not want the soap to interfere with the undercoating.

6. Sand down the metal parts

Sanding the undercarriage of your vehicle before adding an undercoat is very important. By sanding down the metal parts, you are actually removing any rust and leftover grime. This will allow for the undercoat to bond easier with the metal surface and protect it better.

Sanding down the undercarriage of a car is not a difficult task. First, you’ll need to gather some supplies. You’ll need sandpaper in various grits, a dust mask, eye protection, and a power sander. If you do not have a power sander, you can also do it by hand using sandpaper or a wire brush.

Next, start with a coarse grit sandpaper and work your way up to a finer grit. The key is to take your time and be careful not to damage the metal. When you’re finished sanding, make sure to clean off the area from dust residue.

7. Apply the undercoating spray

At this point, the undercarriage should be washed, dried, and sanded. If this is the case, it is time to apply the undercoating spray. Grab the undercoating spray and shake it well before using it. You can start from anywhere. Personally, I always start from behind the wheel. I do all four wheels first and then I move under the vehicle. Make sure that you are spraying the undercoat on all metal parts. Do not worry if you get some of the undercoating spray on stuff like plastic, shocks, studs, wiring, etc. This stuff is not abrasive and will not damage them.

The most mistake people do here in this step is not having enough undercoating sprays. If you are doing it for the first time, you might know how many sprays you need. This is why it’s best if you get a pack of six. You will also need the undercoating spray for the next time.

8. Keep the coatings from being rubbed off

We all know that while driving, many stuff gets under the car that can chip the undercoating. In places where there is no undercoating layer, the metal is not protected from salt. This is why it’s important to get under the vehicle from time to time and inspect the condition.

Your undercarriage will be protected from salt as long as you keep the coatings from being rubbed off or cracked off. If you get in a wreck and you do not reseal the coating, your car won’t be protected from the salt.

Where Should You Not Spray Undercoating?

Undercoating your car is important to protect it from corrosion, but you should avoid spraying undercoating on certain car parts. Undercoating can trap moisture and cause rusting. You should avoid spraying undercoating on brake rotors, brake drums, rubber, sensors, cameras, driveshaft, tires, and parts that get hot like the exhaust and engine.

Car Care Hacks

Hi there. I am a certified Automotive Service Excellence (ASE) mechanic since 2018 and a car detailer for 10 years.

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