Definitive Guide to Pressure Washing Your Car

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Definitive Guide to Pressure Washing Your Car

If you’re looking to elevate your car washing game – using a pressure washer with a foam cannon is Mount Everest level. A high-pressure washer is the tool of choice for professional detailers across the globe for a reason.

Their ability to supply a high volume of pressurized water and ultra-sudsy car shampoo helps to remove dirt, stuck on debris, and other contaminants quickly and efficiently.

But pressure washing your car with a detergent and/or car shampoo does come with some risks, recommendations, and best practices. This is what we’ll explore today. In the information below, we’ll provide a definitive guide to pressure washing a car, truck, or SUV.

So – let’s turn that pressure nob to 11 and get cracking.

What are the Benefits to Pressure Washing Your Car?

A car pressure washer or high-pressure water sprayer as some call it, is designed to provide a focused stream of water. There are multiple types of spray nozzles – each designed for a higher or lower pressurized stream.

When you configure a pressure washer for optimal use in car washing it can accelerate the time needed for pre-washing, improve ability to rinse soap completely, and when attached to a foam cannon, apply a liberal amount of super-thick suds for improved lubrication.

Using a pressure washer for car cleaning can likewise improve your ability to remove caked on brake dust, mud, and even sticky bug guts and bird droppings.

What are the Risks to Pressure Washing Your Car?

The pressure washer is not the end all to be all solution for car washing. In fact, if you use the wrong settings, incorrect adapters, or the wrong soaps for foam cannons, it can lead to some problems including:

Chipping Paint: Did you know that most pressure washing machines are used to remove spray paint or graffiti from brick, concrete and metal fences? That’s a lot of high pressure. Imagine what that would do to your (relatively) soft paint?

Scratching: Pressure washers can also provide a false sense of security for car owners, as they’ll forget to completely remove residual soap when rinsing. If this happens, and you dry the vehicle with standing soap, it can lead to scratching and marring.

Gotta Use the Right Settings: As we’ll explain further below, when you use a high-pressure washer on your ride, it’s CRUCIAL to use the right settings and nozzles. Also, you need to make sure to use the correct support tools, like spray wands or nozzles, foam cannons and shampoo (at the correct ratio).

Most pressure washers will have an easy to access holder for tips. This allows you to swap them out quickly for different cleaning tasks.

I’m not saying it takes a doctorate in rocket science to operate a high-pressure washer for car cleaning, but some common sense and understanding of how they work will go a long way to reduce issues.

Pressure Washing FAQs

So, you’re thinking about upgrading to a pressure washer to complete routine car washes – now what? How do you pick a good one? Is there a difference between electric or gas powered? Is money the determining factor that equals the best one?

Let’s answer some of these common pressure washer FAQs

1 -- How do I choose the right pressure washer for car washing?

The best type of pressure washer for automotive applications is an electric powered one with custom settings for PSI (pounds per square inch) and GPM (water flow measured in gallons per minute). The combination of these two equal cleaning units (or 1000 PSI x 2 GPM = 2,000 CU).

There are two types of power washers -- gas powered (on the left) and electric powered (on the right).

The optimal CU for washing most cars, trucks, and SUVs ranges from 1,900 to 2,800 CU. Most electric power washers have this capability, so that’s the route I would suggest. Also, make sure your electric pressure washer can use an extension cord for power. Many of them require direct power with specific outlets.

If you’re looking for mobile solution – the gas pressure washers are probably best – unless you have a portable generator.

2 -- Is there a certain tip or nozzle that’s best for washing cars?

There are two schools of thought here. First, is it best to have larger area coverage or a more focused stream? A narrow gas pressure washer tip will cover less surface area to clean your car, but it’s requires more pressure for a focused stream.

This is a great method for washing wheels, especially when there is a lot of brake dust caked or mud under the fender.

The larger or wider tip covers a larger area – but with less pressure. So, this is best for your normal car washing, maintenance and even decontamination washes.

3 -- What is the best tool to use with high pressure washers?

There is a difference between a foam cannon and a foam gun.

A foam cannon is attached to a high-pressure hose, has a larger container or cannister, and uses the accelerated pressure to provide a more rich and thick foam on the vehicle surface. A foam gun is smaller and attaches to a normal spray nozzle and hose.

A foam cannon + a sudsy, ultra-foaming car shampoo produces this type of thick foam.

If you’re going to invest in a high-pressure washer, why not go full throttle and get yourself a good foam cannon. It’s a good idea to purchase one that has a dedicated spray nozzle, with quick connect fittings for easier swapping from rinse to wash mode.

Steps for Washing a Car using a Pressure Washer

There are two ways to utilize a pressure washer when it comes to car washing. Option “A” is to simply use the washer to rinse – or Option “B” -- as a touchless car wash solution. Most car enthusiasts opt for the second choice, simply because it allows you to maximize cleaning potential.

So, let’s assume that you’re going to use the high-pressure sprayer to pre-wash, and rinse your vehicle. Here is the best way to accomplish this task.

First – Clear a Flat Space to Wash Your Ride

There are several hoses involved in using a high-pressure washer. As such, this represents an honest safety concern (specifically tripping). To reduce the potential of this happening, make sure to wash your car on a flat surface – or at least an area with plenty of space to walk around the vehicle.

Second – Set the Pressure Washer Correctly

The next step is to collect your supplies and set the pressure washer for car applications. Always refer to the instructions and directions provided by the manufacturer – as each type of pressure washer is unique and has different ways of setting PSI and GPM water flow.

One often skipped item in this step is remembering to check that the nozzle is the correct for your application. Most people use the pressure washer for different tasks, like windows, decks, and more. It’s always best to use a white-tipped nozzle, with a large, low PSI water output.

Third – Pre-Wash the Vehicle

This is a two-step solution. First, spray the entire vehicle with water, making sure to remove as much standing debris as possible. Second, set up your foam cannon.

The car shampoo you will use should have precise instructions on how much soap to use in a foam cannon or foam gun. Always follow the SOAPS recommendations – not the foam cannon manufacturer. This is the variable that really matters.

The Best Way To Use A Foam Cannon - Throw Away Grit Guard!

Here are three best practices for foam cannon use – but again, always defer to the shampoo’s instructions.

Fill the foam cannon basin with warm water – about ¾ to the top. Warm water helps agitate the shampoo for a thicker application.

Shake the cannon basin once it’s attached. Not aggressively, just enough to blend the shampoo and water.

Spray the foam cannon solution on the entire vehicle. Start from top to bottom, working left to right. Don’t be afraid to adjust the foam cannon settings (if applicable) for the desired level of foam.

Let the shampoo soak on the vehicle for a few minutes. I usually let it sit for about three minutes, then use a paint brush with fine, scratch free fibers to agitate the soap on wheels – to help clean the wheels that way. But I’ve got Armor Shield IX applied to my wheels, which helps expedite the cleaning of wheels BIG TIME.

Fourth – Make the Decision – Wash or Rinse – then Wash

The next step is to make an important decision. Do you go directly to the wash method (using the foamy soap as extra lubricant) or rinse it off, then wash with fresh shampoo via the two-bucket method. This is honestly a personal choice, as there are pros and cons of each.

Some people swear by using the foam as the ultimate lubricant, but others think rinsing off that dirty soap and rewashing with fresh shampoo via the two-bucket method is best.

I choose a hybrid – and use the pressure washer to remove standing dirt -- then foam cannon/foam gun as a pre-wash agent to apply the soapy solution, wash with a few wash mitts, then rinse completely off -- like the video above displays.

Finally – Rinse Completely

When you’re finished, rinse the entire vehicle. We always recommend rinsing off sections as you go – with the two-bucket method. But, always rinse the entire vehicle with the pressure washer. Especially those nooks and crannies.

When you’re finished using the pressure washer, make sure to disconnect water lines and let them drain completely. This will reduce standing water inside the hose, and the potential of corrosion or developing bacteria.

Wrapping it Up

A pressure washer is a great tool for washing your car, truck or SUV. It’s especially helpful when you’ve gone off-road or after a snowstorm. Using it as it’s designed will help get the most bang for your buck. But, it’s also important to use the right automotive shampoo – especially if you are going to use a foam cannon.

A car shampoo that is pH neutral, ultra-sudsy and is concentrated solution (meaning using less than 4 ounces per foam cannon) will produce the best results.

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Tim C

Tim is part of the AvalonKing team as a content editor. He is a 30-year automotive industry insider and accomplished publicist & columnist.