Washing with a pressure washer
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Joined: Sep 2007
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From: Texas
'08 GL 320CDI
Washing with a pressure washer
I'm just curious if there is anyone out there who has had success using a pressure washer when washing your vehicle. Most reports I've read warn against using such a device for fear of possible paint damage. I can see that with the higher PSI washers, but thought a washer with a lower PSI would be safer and be more effective than pressure from a normal hose. The normal water pressure at my house is quite good, but no match for a lower PSI pressure washer. I've been thinking of getting a pressure washer for other reasons as well, i.e. cleaning our deck and walks etc.. Any advice you might have, including the brand and model number of your washer, will be greatly appreciated.
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From: Los Angeles, CA
2008 S65 AMG, 2005 SLR McLaren
IMHO, ..I would strongly advise to NOT use a power washer to clean your vehicle! 
Why take the risk of paint or body damage to your vehicle, a regular garden hose has enough water flow to clean any type of vehicle without the risk of damage.
Why take the risk of paint or body damage to your vehicle, a regular garden hose has enough water flow to clean any type of vehicle without the risk of damage.
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Joined: Aug 2007
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From: Iceland
2007 GL450 PE
I have used pressure washers for years on my cars. They will get the dirt that is stuck off the paint before you use the spong + warm water + car soap on it.
Normal hose pressure wont get stuck dirt off.
If I remember correctly anything below around 110 PSI is safe, I would not use something like 130+ PSI on it. The paint on the car itself can probably handle higher pressures but the first paint that comes off using too much pressure is the paint on the plastic parts...
Orn
Normal hose pressure wont get stuck dirt off.
If I remember correctly anything below around 110 PSI is safe, I would not use something like 130+ PSI on it. The paint on the car itself can probably handle higher pressures but the first paint that comes off using too much pressure is the paint on the plastic parts...
Orn
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13 ML350
using a pressure washer is fine as long as it's not too high powered.
I have a Karcher from Home Depot and use the adjustable tip wand.
With any high pressure product, don't put it too close to the surface and it's best to use a smooth sweeping motion across (don't let it sit too long on one spot).
You really should look at a presoak/foam gun first before washing. That will help you get off a lot of stubborn stuck on dirt.
I have a Karcher from Home Depot and use the adjustable tip wand.
With any high pressure product, don't put it too close to the surface and it's best to use a smooth sweeping motion across (don't let it sit too long on one spot).
You really should look at a presoak/foam gun first before washing. That will help you get off a lot of stubborn stuck on dirt.
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Joined: Oct 2007
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2008 F-250, 2007 GL450
I noticed my boss had very little swirl marks on his trucks and they are relatively clean most of the time. I found out he uses a pressure washer which surprised me. I can think of much worse ways to treat your paint. Unless you’re a detail fanatic like me willing to spend a lot of time it’s probably not a bad way to go.
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From: Spicewood, TX
2008 GL 320, 2007 Silverado LTZ C3500 Duramax Turbo Diesel
As stated, pressure washers are fine as long as used properly. Many of them have changeable or adjustable spray nozzles. You want to use one with the widest spray pattern, that does not concentrate the spray in a small area. Don't get too close 8"-12" and don't hold it in one place for any length of time.
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From: Spicewood, TX
2008 GL 320, 2007 Silverado LTZ C3500 Duramax Turbo Diesel
Unless you hand wash, they are all pressure washers, just built-in instead of portable. Personally, I find it more convenient to stop at a manual car wash than to drag out my pressure washer, hook up hoses, and mix a batch of car wash soap for the injector.
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Thread Starter
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Joined: Sep 2007
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From: Texas
'08 GL 320CDI
That's probably what I'll end up doing as well. I used one of those manual car wash facilities a couple of weeks ago in Chicago as a result of a lot of salt and grime accumulating on my truck. It was the first time I've ever used one and I couldn't believe how fast it went with a pressure washer. After reading some of the comments here, which I do appreciate, I think I'll only do this on rare occasions when the vehicle is really filthy, which doesn't happen all that often here in Texas. It's not worth risking possible paint damage.
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13 ML350
In addition to a pressure washer, you need to use a soap and sponge.
If you wash it the wrong way, you'll get scratches. Sure if you have pre-existing paint chips and use a high pressure washer with a concentrated attachment, you'll ruin things for sure.
Go to Autopia or any other car detailer site. It's been discussed to death
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Joined: Apr 2006
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From: Florida, USA
2017 Rolls Royce Wraith, 1999 CLK Cabriolet, 2023 Genesis G90
I have used the same carwash for the last 25 years and have never had a problem. Their machine, as do most automatic set-ups, uses high pressure nozzles and when my cars are just about to enter the tunnel, the guys presoak them with the pressure wands. Thus far, I have never had any paint damage. The original machine was a "Hannah" brushless, and it's still essentially the same, although it has been updated over the years. As far as using a hand-held pressure washer, I would be extra careful because in an instant one can stop over an area and damage the paint if the pressure is too high.
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2007 ML 500
if you use the correct psi, its better for your cars paint as it will have less swirl marks.
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From: Scottsdale, AZ
2004 RX330, 2008 Scion xB, 2001 Honda Insight Hybrid, 2010 Toyot Prius v ATP
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2008 F-250, 2007 GL450
These can leave swirl marks. So can just about anything including towels, mitts, pressure washers. They mostly do it by dragging the dirt, esp. large particles, across the paint. Putting the washer nozzle right up next to the surface or at high pressure will grind particles across paint. More reasonable use of the washer won’t get the road film off and will make the paint look slightly dull. The dull look gets worse with time and leaves contaminants to start bonding into the paint. So if you want to use the pressure washer you should still actually wash the car once in a while. If you use the self serve car wash, as I usually do, don’t use their brush. You don’t know where that thing has been and most are built for durability not gentleness. Automatic car washes are notorious for leaving swirls.
I’ve been pleasantly surprised that the Ceramiclear paint on my GL lives up to its promise by being extremely scratch resistant. So in some ways I’m now actually less careful with my Mercedes than my Ford or other vehicles. I always use a 100% sheepskin mitt to wash regardless.
I’ve been pleasantly surprised that the Ceramiclear paint on my GL lives up to its promise by being extremely scratch resistant. So in some ways I’m now actually less careful with my Mercedes than my Ford or other vehicles. I always use a 100% sheepskin mitt to wash regardless.
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From: Scottsdale, AZ
2004 RX330, 2008 Scion xB, 2001 Honda Insight Hybrid, 2010 Toyot Prius v ATP
That said, thank you for the advice. I'll be sure to put it to good use!
STP
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From: B.C.
GL 320cdi, Chevrolet Avalanchero, GLE 350 (on order)
Handwashing in public is against the bylaws here, as is allowing soap to enter a gutter.
As such, I always pressure wash at the coin wash about 2 blocks from my place. When I get home I hand dry the car with a light mist of instant detailer, to lubricate any dirt and road grime, with clean polyester towels. Works great, and prevents haze. Also makes your car so shiny, it looks like it is made of corn syrup.
No swirlies, except when some slob dragged his *** across my rear quarter pannel at the parking lot when my car was dusty.
As such, I always pressure wash at the coin wash about 2 blocks from my place. When I get home I hand dry the car with a light mist of instant detailer, to lubricate any dirt and road grime, with clean polyester towels. Works great, and prevents haze. Also makes your car so shiny, it looks like it is made of corn syrup.
No swirlies, except when some slob dragged his *** across my rear quarter pannel at the parking lot when my car was dusty.
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C32 AMG
I've never been able to get road grime off a car without some physical contact (soft brush, sponge, rag) even with a power washer. Even at the car wash, they use mechanical brushes and cloth.
Some of it is regional. In dry, warm areas, you have a LOT less road scum to deal with. Those of us in wintery/rainy areas often wonder how anyone can keep a car clean with just a "california brush."
Some of it is regional. In dry, warm areas, you have a LOT less road scum to deal with. Those of us in wintery/rainy areas often wonder how anyone can keep a car clean with just a "california brush."
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From: Elk Grove, CA
2013 Land Cruiser, 2007 GL450 [SOLD], 2007 Toyota Tundra Double Cab 4x4 Limited, 2009 Corolla LE
I thought I read in the manual that do not use pressure washer on the parking sensors (parktronics) and other delicate parts. But, front bumper is one that gets all the bugs in summer and they only come off either by pre soaking or pressure washing. you just need to be carefull around the parking sensors. here my 0.02 cents.
