Complete Guide To Car Undercarriage Wash

Washing the Undercarriage of A Car: Dummy’s Guide

Last Updated on September 5, 2023 by Chase Manhattan

Washing the undercarriage of a car is not something that most people think about every day is it?

If it’s been a while since your last undercarriage wash, you might be in for a rude awakening. Keep reading after this video to find out how to perform an under carriage car wash, and why it’s important that you do.

How To Clean The Undercarriage of A Car

Wash The Undercarriage Of A Vehicle

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Check for Skid Plate

Not every car comes equipped with a skidplate, but newer model years and European cars will have them more frequently. Remove the skid plate if necessary or preferred. Check that the car manufacturer does not have any advisements against washing the cars undercarriage.

Lift The Car

You should not use a pressure washer on the car if it’s close to the ground as rocks will jump off the ground from the water pressure. There is a higher risk of critical components getting damaged this way. Instead, lift the car if you have a kind of lift, use jack stands if it’s your only option. Otherwise make sure the surface below the car is clean.

Remove The Wheels

This is not required, but is highly suggested. Removing the wheels will allow you to access the wheel wells which is one of the hard to reach areas that is prone to developing rust and corrosion. With the wheels gone, you can take the opportunity to rotate your tires, or power wash other tight spaces while they’re accessible.

Treat Clean Parts

As I mentioned, there are some parts of the undercarriage that you should be mindful of using a pressure washer on. It’s best to cover these parts if you plan on avoiding them, but I also recommend you cover clean parts or spray them with WD-40 to prevent rust. You can also use an undercarriage cleaner/protectant in the same way.

Rinse The Undercarriage

You can use a garden hose or a pressure washer to wash your undercarriage. In my experience, the preferred option here is the power washer. Pressure washers and the like spray at a higher velocity (PSI or Pounds per Square Inch) which will remove any debris that has stuck to the undercarriage.

If you prefer to use a hose, this is an option as well. It will efficiently rinse the surface, but you may need to brush any road salt that is strongly stuck to the underside.

Wash your car with warm water whenever possible.

Apply A Cleaning Agent

This is another opportunity to apply the surface protectant to the undercarriage. Some people prefer WD-40 or its substitutes, but you can also use a penetrant oil, or a specific car wash cleaning product for a car undercarriage.

Read next: Best Undercarriage Cleaner

Dry the Undercarriage

You can use compressed air, a dedicated car dryer, or a leaf blower to dry the undercarriage, or a drying towel/soft cloth but I personally recommended a method that moves air as it will allow you to dry the harder to reach areas. Make sure the car is completely dry before you allow it to sit.

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Why Washing The Undercarriage of A Car Is Important

A car’s undercarriage is actually the most important part of the vehicle; without it, you wouldn’t have a driving vehicle. You would have an immobile pile of miscellaneous parts.

The vehicle’s undercarriage is the part of the car that houses some of the most crucial components of your car. It is typically the only area in which the vehicle’s frame is exposed which opens it up to loose contaminants like road salts, mud, road grime, and fuel contaminants amongst other things.

A regular undercarriage car wash is absolutely paramount to protect your undercarriage from rust.

If corrosion has a chance to set in on your car, it can be very difficult to fully eliminate it. Rust is inherently resistant to most things, and has the ability to – basically – multiply itself.

If you regularly clean the undercarriage, you will eliminate any winter salt, dirt, or other contaminants, before they have a chance to develop into rust.

How Often Should I Wash The Undercarriage

The straightforward answer is to clean the undercarriage as frequently as it needs to be to prevent corrosion from forming.

In reality, this isn’t always realistic, so we recommend a regular cleaning every two weeks during the winter months. You can stretch this some, as you see fit, during the warmer months since there will not be the same amount of salt on the road.

My principal for routine maintenance is this: it’s easier cleaning something that has been cared for, instead of trying to maintain something that has been neglected.

Clean the undercarriage regularly and you’ll never have to worry about removing rust.

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What Happens If I Don’t Wash My Undercarriage

Short answer, if you neglect to wash your undercarriage, your vehicles undercarriage will begin to decay due to the spray of salt, road grime, and other contaminants, that your undercarriage is exposed to.

Long answer, I can’t guarantee that any thing will happen if you don’t wash your undercarriage; but, I can strongly suggest that neglecting your undercarriage gives you a higher probability of developing corrosion in its lifetime.

Corrosion – or rust particularly – can create a number of issues for your vehicle, aside from deteriorating the integrity of car.

Corrosion will effect all metal components if exposed for a long enough period of time. This means that, there is the potential for a catastrophic failure in a component like the fuel lines, the exhaust system, or the brake lines.

While, an exhaust or fuel related issue can range in severity, a brake line failure tends to be much more catastrophic by nature. What if we’re talking commercial size vehicles here? Speaking as a business owner, I can easily see a commercial car owner letting the road salt pile up for “just another day”.

Next time you’re in a coastal area, or an area that experiences heavy winters, look for the nearest lifted truck and tell me if they keep the car’s undercarriage clean. If they don’t, it will be a perfect example of corrosion that can overtake an entire vehicle. If they do clean the undercarriage regularly, the wheels, the wheel wells, and even the hard to reach areas, will be sparking clean.

It’s important for me to stress that a frequent car wash and car undercarriage cleaning are paramount practices to maintaining the longevity of your car.

Some elbow grease and a thorough rinse will be enough to keep an already clean undercarriage, clean. Should this not be enough, what do you do? Keep reading to find out.

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Washing The Undercarriage Of A Car At Home

Can I Wash The Undercarriage At Home

An undercarriage cleaning can be accomplished at home, or it can be a service sought from a professional car wash. I’ll discuss washing a car’s undercarriage at home first.

It’s important for car owners to know that a car undercarriage cleaning has become increasingly accessible; it’s no longer kept to the professional car wash providers. This is in part, due to specific undercarriage cleaning products that have begun to hit the market, and advancements in automatic car wash technology – which we’ll discuss later.

These products I’m referencing are pressure washer attachments that are designed to provide a proper cleaning to the undercarriage of a vehicle. One such product being the WARMQ 2-in-1 Pressure Washer, seen below.

Warm-Q Undercarriage Cleaner / Pressure Washer Stock Image

This undercarriage cleaner applies a pressure spray directly to the undercarriage of your car which makes a proper maintenance routine easier than ever. If you’re worried about undercarriage damage from pressure washers, keep on reading.

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Is It Safe To Use A Pressure Washer on A Car’s Undercarriage

Yes, a car’s undercarriage can be pressure washed, but there are some things to be mindful of before doing so. It is the car’s undercarriage that is safe to wash, this doesn’t mean that it’s ok to spray any and every one of the crucial components that may be exposed. When possible, it’s best to survey the car’s undercarriage prior to any pressure washing.

Some manufacturers equip their vehicles with skid plates which are designed specifically to protect the car’s undercarriage from road debris, if your car has a skid plate you will need to remove it to pressure wash your undercarriage, but you also run the risk of damaging the skid plate should you pressure wash it directly.

Should you still be concerned about using a power washer on the car, understand that even the strongest power washer can be moderated.

I recommend using an adjustable pressure washer tip that will allow you to moderate the PSI (pounds per square inch) of the water pressure that is leaving the nozzle.

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Will An Automatic Car Wash Do an Undercarriage Cleaning

Should you decide not to do an undercarriage wash at home, washing your car with automatic car washes are a great way to maintain the surface of your undercarriage without too much extra work.

The undercarriage car wash will follow roughly the same procedure as the steps we took at home, except without having to lift the vehicle. As most of these car washes have an open “pit” area that you drive onto, your undercarriage will be exposed which will allow the car washes pressure washer to easily remove dirt, road salts, and grime from the surface without the need for a brush. Some car washes do offer a brush option, but it is a wise decision to avoid them when possible as they can grab onto any pieces that may be hanging under your car.

Benefits of Automatic Car Washes

While an automatic car wash is typically advised against, these car washes are actually a great alternative to clean the undercarriage of your car. When overlooking the possibility of developing swirl marks in these car washes, an automatic car wash will still provide a thorough cleaning to the undercarriage of the car, while applying a protective cleaning agent and reaching any hard to reach area. Automatic car washes are able to accomplish this by using a pressure washer wand, scrolling underneath the car, to remove dirt, mud, and other materials stuck to the undercarriage.

Drawbacks of Automatic Car Washes

While it’s true that automatic car washes have come a long way, I still feel obligated to advise everyone that they are one of the predominant ways that develop swirl marks on a car – this is why a professional car wash is important. A car wash, when done correctly, is a procedure that is carefully gone through while taking many precautions to avoiding damage the surface of the car. In automatic car washes, your vehicle is more frequently exposed to abrasive properties from brushes and sweeps that have not been cleaned, yet have come into contact with dirty surfaces.

Can I Get My Car Undercarriage Cleaning Done Professionally?

Should You Clean The Undercarriage Of A Car

Another professional method, aside from an automatic car wash, is to take your vehicle to a dedicated car detailing service provider.

These professionals are well versed in washing a car’s undercarriage, and will follow roughly the same procedure we gave you to wash the car at home. The difference here being, these professionals will be able to spot any previously unnoticed undercarriage damage, while also being careful to avoid any brake lines, fuel lines, or otherwise critical components. They will clean the undercarriage with pressure washers until the surface is thoroughly washed with no dirt remaining. They will then let it dry completely and apply a WD-40 spray, or an undercarriage cleaner which will provide the same effect.

Since you’re already at a detail shop, now would be a great time to inquire about a ceramic coating for your vehicle.

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Frequently Asked Questions

Can You Apply Ceramic Coating to a Vehicle’s Undercarriage

Yes, ceramic coating can be applied to the undercarriage of a vehicle, but it is usually best performed by professionals. Otherwise, it is usually referred to as an undercoating. A ceramic coating is for the paint layers of your vehicle but they will both offer roughly the same effect.

Can I Wash The Undercarriage Too Much

While cars are vulnerable to abuse, I would say that cleaning your vehicle too much is not the worst thing you could do to it. Regular washing of your car is one of the best way to extend its lifespan, unbeknownst to most. A dirty undercarriage will allow dirt to build up in odd spots, creating an environment for corrosion to set in, eventually leading to further problems with your vehicle.

Can I Paint The Underside Of The Car

Most vehicle owners don’t know this, but the undercarriage is actually “painted” already. The paint is actually a sealing material that is designed to protect the surface. This is why regular cleaning is so important. During an undercarriage wash we are removing the contaminants that eventually eat away at this coating. In other words, we’ll leave the paint application to the professionals and stick to cleaning our vehicle regularly.

Will Paint Decay Like The Frame Of The Car?

Yes, paint can be subjected to the same decay as a car’s frame. Typically, it takes longer to get there as paint is applied in layers that are ultimately protecting the car’s bare surface. Some people opt for an additional protective layer by applying a ceramic coating.

How Do You Clean The Undercarriage of A Car Without a Hose?

While it is possible to clean the undercarriage of a car without a hose, I wouldn’t advise it as it’s not practical and often does not provide the best results. An alternative here is to take your car to an automatic car wash as automatic car washes have developed technology to easily clean the undercarriage while applying a cleaning agent to prevent corrosion in the future.

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