Many do-it-yourself auto enthusiasts promote pressure washing to get all the dirt off your car and leave it looking like new. This cleaning method is also viewed as a more efficient shortcut to hand-washing and waxing the exterior.
Especially due to the current circumstances, pressure washing your car at home seems like the ideal option. Yet not fully understanding how to use a pressure washer can wreak havoc on your car, stripping off the paint, exposing the metal underneath and leading to potential rust damage.
Before taking on this DIY project, here’s what you should know.
How to Correctly Pressure Wash a Car
Contrary to popular belief, pressure washing involves more than a steady, high-powered stream of water delivered from a hose.
Rather, systems are electric or gas-powered, PSI is variable and essential to not cause damage and the nozzle can be angled a number of ways. Also, several systems let you add soap or a cleaner, so you’re using more than water.
To prevent stripping off your car’s paint, be mindful of the following:
- PSI and GPM: Both terms relate to the flow of water but mean different things. PSI (pounds per square inch) pertains to the pressure at which it’s released, while GPM (gallons per minute) is the amount of water released. When these are multiplied, you get the number of cleaning units for a surface. For a typical car, use 1,200 to 1,900 PSI and 1.4 to 1.6 GPM for 1,900 to 2,800 cleaning units. Anything above risks the car’s coating and paint.
- Electric vs. Gas: In general, gas-powered pressure washers tend to deliver more power. For these types of projects, make sure you’re using an electric unit – not only do you risk stripping off the paint, but the PSI could crack your car’s windows.
- Nozzle Angle: Pressure washer nozzles range from 0 to 65 degrees, with lower angles delivering a direct, targeted stream. As such, anything above 15 degrees is ideal for rinsing off a car or applying soap, while below is too strong for the paint.
- Where You Park: Pressure washing has the potential to damage your home’s surroundings, be it plants, fencing or pavement and can also cause injury. Before you pressure wash the vehicle, make sure it’s away from other objects, people and pets.
Once you’ve considered these factors, make sure the windows, doors and trunk are closed before rinsing off any mud and debris, standing at least four to five feet from the vehicle. Also be ready to use detergent, compatible with both the pressure washer and your car, after the initial rinse.
If you decide to use a brush with the pressure washer, make sure it’s free of dirt and debris. Otherwise, the high-powered stream and these finer particles can scratch the car’s surface.
Wear closed-toes shoes when you clean in case the spray comes in contact with your foot. Pressure washer PSI can be strong enough to take skin off.
What Can Go Wrong
Due to the potential risks, Consumer Reports recommends not pressure washing your car. Among the biggest concerns, high PSI can strip off or scratch the paint, leading rust to penetrate the metal. In relation to where you wash, the high-powered stream can cause pebbles, gravel and dirt to scrape against the surface.
Beyond the big-picture issues, pressure washing a car often does more harm than good, especially if you have less experience:
- Car owners attempting this project often fail to first clean off the car’s surface and undercarriage fully. Doing so leaves dirt on the surface that, when combined with the pressure washer’s heavy stream, turns abrasive and can leave scratches all over the paint.
- If the paint is already chipped, a pressure washer often causes these cracks to widen or the paint to peel off, resulting in more damage.
- Because age plays a factor in how soon a car will rust, you should avoid pressure washing older, classic vehicles.
- The car owner doesn’t know how to use the pressure washer correctly. This inexperience may manifest as standing too close to the vehicle, using a PSI setting that’s too high, washing from bottom to top, leaving the stream in one place for too long or washing the car in an area near fragile materials or gravel.
- Certain parts of a vehicle should never be pressure washed like the engine, under the hood and anything made of plastic or rubber. However, the stream at a low-pressure setting can help remove mud, salt and debris from the undercarriage.
- Although detergent helps fully clean off the car, some attempt to use dish or laundry – neither which should be used on a vehicle – and don’t dilute the substance properly before starting.
Rather than dealing with the consequences of pressure washing your vehicle, bring it to DaSilva’s Auto Body for exterior detailing and rust removal services. To make an appointment, contact our Naugatuck shop today.