How To Wash The Undercarriage Of Your Car? THE GUIDE


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car undercarriage

One of the most neglected areas of cars when it comes to cleaning is the bottom. Luckily, washing the undercarriage of your car is a straightforward process and doesn’t require some specific knowledge. Anyone can learn it in a few simple steps. Today, I’ll show you my thorough guide on how to clean the dirty undercarriage of your car. 

Most car owners and car washing services don’t care so much about the car’s undercarriage. In my opinion, that should change as soon as possible. Most of the road dirt, grime, salt, etc. end up stuck somewhere in the undercarriage, which can lead to rust, which can again lead to mechanical damage to the drivetrain, suspension system, chassis, and other car parts, too. 

Many people wonder if it’s safe to wash the undercarriage of their car (check my detailed article about it), and as long as you follow some guidelines, it’s completely safe. Not only it’s safe, but I would also say that it’s crucial for keeping your car rust-free for years.

Washing The Car’s Undercarriage: Step-By-Step Guide

Without further ado, let’s see the step-by-step guide for washing the undercarriage on cars, trucks, etc. Also, I’ll try to make it as simple as possible, so you don’t need a lot of additional equipment such as car jacks, etc. You’ll only need a few pieces of equipment and you’re good to go.

What You’ll Need:

1. Prepare The Equipment

Before you start washing, you should ensure that all the equipment is properly connected and that it’s working. 

Connect the pressure washer to the water source, and then connect the undercarriage cleaner to the pressure washer wand. It’s a very simple process which you can check on the link to the product (above). When you connect it, try running it to check if everything works fine.

If you don’t have a pressure washer and the undercarriage cleaner, just prepare a garden hose, but also prepare yourself to end-up wet since you’ll have to bend down to grasp all the undercarriage parts (that’s the main reason why I recommend using specialized tools such as undercarriage washer).

2. Pre-Treat The Area With an APC (Optional)

In most cases, using only plain water is enough to clean the dirty bottom of your car. However, if your car is extremely dirty, you can pre-treat the undercarriage with some all-purpose cleaner.

It may be hard to reach all the areas, but usually, it’s easy to spray an APC on the most important ones such as wheel surrounding areas, suspension, springs, exhaust, etc. After applying, let it sit there for a minute or two, and then proceed with the washing.

3. Thoroughly Wash The Undercarriage

Now that everything’s set up, you should power on your tools and get to the work.

By using an undercarriage cleaner, slowly go around the car and thoroughly wash each part of the undercarriage. Start from the edges, and slowly push the cleaner to the middle of the car.

So, from one side, you’ll be reaching the middle of the vehicle only, and then you should go around the car and do the same, so in the end, everything is completely clean. Pay specific attention to wheels and surrounding areas, because it’s where most of the dirt is trapped.

I like to do the whole process twice, since the first pass will soften the dirt, grime, and salt, while the second pass will completely remove it, leaving the surface perfectly clean.

For those of you who don’t have the needed equipment, you can use a garden hose gun nozzle, and wash the undercarriage with it. You’ll probably be wet by doing so, but I suppose it’s not a big deal.

4. Wash The Rest Of The Car

After you’re finished washing your car’s undercarriage, you can then wash the rest of the car if you want. If you don’t want to do it, you can skip this step.

I won’t write you the steps for washing the exterior of your vehicle, since I have already written a fantastic and thorough guide on that topic, so make sure to check it out:

You may wonder why I suggest washing the undercarriage first. That’s because the undercarriage is usually filthy, and you don’t want all the dirt, grime, and salt to end up on your freshly washed wheels, or even worse, paint. 

5. Let The Car Dry Completely

After washing the undercarriage, I suggest you let your car dries for around 30 minutes. That should be enough time for all the water to get out of the crevices, especially some electric parts such as ABS sensors, etc. 

There’s a very little chance that you could screw something up by driving the car immediately, but an extra step of security will remove all possibilities of causing any damage to your vehicle. 

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Why It’s Important To Use The Undercarriage Cleaner/Washer?

Undercarriage cleaners are specifically created for washing car chassis. They’re completely safe for both electrical and mechanical parts, and they make the whole washing process easier.

Without them, it’s much harder to wash the undercarriage, since you’ll have to bend down and reach all of the undercarriage areas with your hand and a garden hose. Together with back pain, you’ll probably end up all wet and dirty from the water. And by using an undercarriage cleaner, you won’t have any of these problems.

They’re not expensive, and I think it’s completely worth spending 20-40 bucks for an addon that’ll help you clean and maintain your car, and will also last for years.

Frequently Asked Questions

As usual, there are many questions people usually ask about washing the undercarriage, and I decided to give you an answer for the most common ones.

Can I Use a Pressure Washer To Wash The Undercarriage?

I don’t suggest using a pressure washer only since it’s usually too strong (too much PSI), which can lead to some damage to the car’s suspension system, drivetrain, electronics, etc. However, if you still decide to use a pressure washer, make sure to point the wand at an angle (20-30 degrees), and keep it as far away from the undercarriage as you can.

Do I Need To Use Some Kind Of Soap To Wash The Undercarriage?

In my opinion, using plain water only is completely enough to wash the undercarriage. However, if you’d like to use anything, I suggest using an APC (All-purpose cleaner). Just spray it over the undercarriage, let it sit for a minute or two, and then proceed with the wash.

How To Avoid Water Hitting Electrically Sensitive Areas?

Well, you can’t avoid water from hitting electrically sensitive areas. Luckily, the electronics on the undercarriage are made to withstand water. As long as you don’t use a high-pressure washer to directly wash the undercarriage, you won’t make any damage.

I’m Experiencing Electrical Issues After an Undercarriage Wash, What To Do?

If you did everything as told in the guide above, there shouldn’t be any damage to the electronics and mechanical parts. However, if you experience some issues, the best thing you can do is disconnect the battery, and let the car dry for an hour or two. After it’s completely dry, everything should be fine. You may need to connect the car to the diagnostic tool to clear any codes, but it should be fine. 

If the issues occur, it’s a sign that the wiring on your vehicle isn’t the best, and you should check it further by going to a mechanic. Electrical installations on the undercarriage are made to withstand water, and if they don’t, something’s wrong with your car – make sure to fix it ASAP, since driving in the rain will cause the same issues.

I Can’t Wash The Undercarriage At Home, What To Do?

If you don’t have all the needed equipment or you need it in an apartment, you should check for automatic car washes that have an undercarriage washing option. Going there is completely fine for washing the undercarriage of your car. However, don’t wash the whole car there since it’ll scratch your paint.

Should I Apply Undercoating To My Car?

Applying undercoating to your car is a fantastic idea to prevent rust. However, make sure that the area is completely clean before you apply any kind of protection. If you apply it on a dirty undercarriage, it’ll only make things worse. So, wash the undercarriage first, then apply some kind of protection (I suggest you pay someone to do it since it’s not a straightforward process).

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