Proper Maintenance of a Vehicle’s Undercarriage

Undercarriage, Show Car Cleaning, Undercarriage cleaning

In the realm of detailing and car maintenance, the undercarriage is often overlooked. A full car detail cannot be complete without paying attention to the bottom side of the car as well.  It’s like spending time in the gym and only doing chest and arm exercises. Sure those areas look great, but you’re neglecting the rest of your body.  So why do you need to care for the undercarriage if no one can see it? Then, how do I do it?

Why is it important? Who does this pertain to? 

There are several reasons why the undercarriage should be tended to on a regular basis.

The most common reason of course is salt on the road in cold climates. Salt is caked on the road when it snows or there is ice. Salt lowers the freezing temperature of water. With salt, snow and ice will melt if it’s already formed and will prevent further ice from accumulating.

The properties of salt make it a catalyst (speeds up the process) for oxidation.Salt Catalyst, Rust, Metal OxidationSalt (NaCl) reacts with the metal and oxygen (O2) in the water to form metal oxide. For the sake of an example, Iron will be used as the metal (Fe) to form oxidized Iron, or rust (Fe2O3). The tricky issue with salt is that it never gets used up. As a catalyst it stays present, it doesn’t go away and awaits for more water to continue the reaction.  Salt is also Hydroscopic, meaning that it attracts water and continues the reaction. THIS IS WHY it is important to get the salt off your car AS SOON AS POSSIBLE.

But if you’re thinking, “hey it doesn’t snow where I live, I don’t have to worry about it”. That is not necessarily the case. If you live near the ocean, salt water can have the same effect on your car.  Although it may not be as much of a direct effect as salt on the road, the salt in the air will eventually take the same toll on the car. Regular maintenance is required to prevent rust from forming.

Alright I’m convinced, what products/material/tools do I use on the undercarriage?

The most crucial piece of equipment you’ll need is a pressure washer.  This is going to provide you with the right amount of force to get all the loose substances off and even some of the tough to remove ones too.  Supplementing this with a strong degreaser is going to help tremendously when cleaning the tough to reach spots.

There are products out there that you could buy when need to be more attentive with your car’s bottom end.  These are for the people that will go the extra mile with a brush and some elbow grease.  These undercarriage products will help when it comes to cleaning, but also when it comes to protecting as well.  However, you need to be careful not to get false products.

False products are basically short cuts. These products are known as “concealers”, and they will only hide the problem, maybe even make the problem worse and won’t last.  For example, you can find concealers for wheel wells where you supposedly don’t have to clean it, just spray the product over it and it makes a nice looking surface.

There are products that will help, but you need to be careful when using.  Products like rubberized undercoating spray can help, but if the surface is even remotely wet or contains moisture, the rubber will trap the moisture in there and actually make the metal rust faster!

Tell me how to do it! 

There are a number of approaches when it comes to the process. The things to consider are your limitations vs. your commitment to detail. What this means is, working with what you have available.

For those of you with lifted trucks, you have the easiest approach here. Just make sure you safely get low enough to view and inspect the entire undercarriage.

For the rest of the automotive world, there are a couple things one could do depending on how much cleaning is needed and what tools are available.

For many people, simply getting most of the salt and contaminants off will be enough for them to call it a day, but by no means does it get the undercarriage completely clean. If you don’t want to spend all day or have the tools to lift the car, here is an article to create your own DIY undercarriage pressure washer. This will be a high pressure system to use force to get most loose contaminants and some tough ones off. It’s not a sure fire way, but it is better than nothing.  If your undercarriage tends to get dirty due to mud, dirt, or fresh salt because of the road surfaces you drive on, this will be a great tool moving forward.

For the rest who can’t fit under their vehicles, it would be best suited to lift your vehicle with steady jacks and remove the wheels. For those who require a lot of detail cleaning (show cars), you would do well to get your car lifted with some sort of mechanical lift system and remove the wheels. This will allow adequate viewing of the undercarriage and likely enough mobility for proper cleaning.

Disclaimer: Make sure all safety precautions have been made before getting underneath the car. Your regular jack on its stand will no be sturdy enough if you are scrubbing hard on your car. Here is a good article to read. Make sure the car is on a level surface and wheels chalked (if working half the car at a time). Scrubbing can cause the vehicle to shake so make sure that it’s properly stabilized.

Now that you are properly positioned to care for the undercarriage with your tools and products available, get ready.  Undercarriage Washing Guide

 1) Thoroughly spray the entire undercarriage of the car with the pressure washer.

- This will remove many contaminants but not all.

2) Call it a day here if you choose to.

3) Grab your degreaser and coat the entire undercarriage. Let it sit for 20 minutes.

4) Repeat Step 1

5) Inspect and spot clean heavily soiled areas with a brush.

6) Repeat Step 1

So now that we’ve cleaned the undercarriage, we have the option to go one step further. How do we protect it? Well, making sure that the undercarriage is completely dry is step 1.

Next is get your products handy.  You have a couple of options. You can go with the rubberized undercarriage spray as was stated earlier. Be mindful to take all necessary steps to dry the car first. Another product can be a simple lubricating oil like WD-40 for example.  This will whip away moisture while protecting the surface without the fear of trapping water. These products will do a great job in keeping moisture away and protecting from salt.

When getting ready to apply the product, it’s a good idea to spray on nuts and bolts around the undercarriage. Stay away from anything engine related (engine, transmission, exhaust) as they will get too hot the product will burn off and smell.  Also be sure not to coat with the panels frequently accessed (i.e. for oil changes) with the rubber spray as it will make it a hassle in the future.  Oil will work best for most metal surfaces like the brake lines and fuel lines that don’t overheat.  The rubberized spray will work best for the nuts and bolts.

Additional Notes

You’ll definitely want to pay special attention to brake lines and fuel lines. They tend to rust the fastest.  Based on their names alone, at the very least you’ll want to care for them if nothing else.

Like many areas of detailing, the best course of action for one car may not be the best action for another.  When referring to undercarriage maintenance, older vehicles require a sense of delicacy.  Older parts that are rusting are likely to break while working on them.  This doesn’t mean that you shouldn’t tend to them. Knowledge and awareness will win you half the battle.

Caring for the undercarriage can be the difference that ensures a car’s life span.