Engine Washing
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W221 S600, W220 S55 AMG Kompressor, W124 300E, W140 S320, W210 E3204M W164 ML320 Bluetec
Engine Washing
Does anyone know if the "official" stance from Mercedes-Benz as to washing the engine bay? Has anyone experienced issues after washing a cold engine and immediately starting and driving the car to operating temperature to dry it off?
I had a 1992 Corvette ZR-1 (4-cam 32-valve engine) back in 1995 and after washing the engine the starter motor had water enter into it and it had to be replaced (it was located underneath the upper intake in the valley pan). Since then, I have been very reluctant to wash an engine and typically just wipe them off as best I can with a towel.
Any experiences/input?
I had a 1992 Corvette ZR-1 (4-cam 32-valve engine) back in 1995 and after washing the engine the starter motor had water enter into it and it had to be replaced (it was located underneath the upper intake in the valley pan). Since then, I have been very reluctant to wash an engine and typically just wipe them off as best I can with a towel.
Any experiences/input?
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Joined: Dec 2008
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From: Rose Creek Golf Club, Edmond, OK
2023 E450W, 2020 GLC300
I've washed the engines in all my cars and motorcycles for many years, but with newer cars I think one has to be more careful of the electronics.
My current method is to get the engine warm, spray it with solvent (Simple Green), rinse with my power washer on the gentlest setting, start the engine and let it run for a while so the heat helps dissipate the water. I don't cover anything, just avoid excessive wetting of any electronics. I think the power washer rinses clean without getting excessive water into the engine bay, and the stream is so gentle it doesn't seem to penetrate where you don't want it.
The only time I've ever had a problem was with an Acura Legend, which would throw an O2 sensor CEL necessitating a reset.
I don't know M-B official policy, but my guess is "don't do it yourself, bring it in to the shop and let us clean it with Liebfraumilch".
My current method is to get the engine warm, spray it with solvent (Simple Green), rinse with my power washer on the gentlest setting, start the engine and let it run for a while so the heat helps dissipate the water. I don't cover anything, just avoid excessive wetting of any electronics. I think the power washer rinses clean without getting excessive water into the engine bay, and the stream is so gentle it doesn't seem to penetrate where you don't want it.
The only time I've ever had a problem was with an Acura Legend, which would throw an O2 sensor CEL necessitating a reset.
I don't know M-B official policy, but my guess is "don't do it yourself, bring it in to the shop and let us clean it with Liebfraumilch".
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From: Clifton, NJ
96 and 08 911 turbos
honestly, unless you are leaking something, or are planning on going to a concours, why bother?
Id just clean the engine cover and maybe wipe down the other plastic parts. No real need to get the soap and water out, given the lower body tray and the huge engine cover.
Id just clean the engine cover and maybe wipe down the other plastic parts. No real need to get the soap and water out, given the lower body tray and the huge engine cover.
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From: California / Hawaii
GL350-Bluetec P1
Polar Bear, I guess I am wondering why you want to wash the engine? Is it for appearance, or do you think it will improve wear / performance? I would be curious to know if there is a benefit to it, and if so how to do it.
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From: Los Angeles
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
I would like to have my engine cleaned as well. I forget what they did last time when I had it detailed because they also cleaned the engine.
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Joined: Sep 2006
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2003 E320
I have washed engines in numerous cars / motorcycles over the years. The ignition systems have improved so that it is unlikely that you will drown one out. As with most endeavors, the more time and effort you apply, the better the results. Pressure washers will certainly test the electrical systems. Degreaser with moderate hosing is less likely to cause a problem. I would not apply water to a running engine nor would I hose down a motor that has been thoroughly warmed up even though the grease is most easily removed when warm. Obviously, spraying water directly into alternator or starter windings is undesireable, ditto air intakes. There is a direct correlation between age and watertight integrity of the motor. Plastics and rubber deteriorate from heat and age. So if it is a 2008, spray away. If it is a 1973, probably better do that near your home or with a good pair of walking shoes. 
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Thread Starter
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W221 S600, W220 S55 AMG Kompressor, W124 300E, W140 S320, W210 E3204M W164 ML320 Bluetec
Some say a clean engine will last longer but who knows. I can see where wetting it (as I have witnessed) can do damage in some cases, so I am a little nervous about taking the hose to it. It's not real dirty by most people's standards, just a little dusty.
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Joined: Nov 2007
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From: NY
'12 Mustang 5.0, '89 Supra Turbo, C55,
You could always remove parts, have them powdercoated, and show off like I do with my Supra 
Notice how dirty my firewall and hoses are. This was without cleaning the engine, but powdercoating stays clean, just wipe off!
I don't recommend power washing. Just take simple green or another degreaser, and elbow grease. Spend a few hours in your engine bay (you did bring up this post, so I imagine you are willing to do that), and clean each component by hand. Even if you don't remove pieces, just use a screwdriver covered in cloth to get to those hard crevices/places. Next time you go to a MB meet, pop your hood and wow everyone!
Today's engines have those ugly plastic covers on them, so there's not much to do, so just hand clean all the pieces you can see, and u're good to go! You could even have the plastic cover painted which looks great.
PS, imagine powdercoating/polishing the supercharger on an AMG engine!!!
Notice how dirty my firewall and hoses are. This was without cleaning the engine, but powdercoating stays clean, just wipe off!I don't recommend power washing. Just take simple green or another degreaser, and elbow grease. Spend a few hours in your engine bay (you did bring up this post, so I imagine you are willing to do that), and clean each component by hand. Even if you don't remove pieces, just use a screwdriver covered in cloth to get to those hard crevices/places. Next time you go to a MB meet, pop your hood and wow everyone!
Today's engines have those ugly plastic covers on them, so there's not much to do, so just hand clean all the pieces you can see, and u're good to go! You could even have the plastic cover painted which looks great.
PS, imagine powdercoating/polishing the supercharger on an AMG engine!!!
Last edited by gnma; Jan 8, 2009 at 09:27 AM.
MBWorld Fanatic!
Joined: Aug 2005
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From: Los Angeles
2009 SL550 Roadster Diamond White, 2008 CLK550 Coupe Obsidian Black
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,691
Likes: 143
W221 S600, W220 S55 AMG Kompressor, W124 300E, W140 S320, W210 E3204M W164 ML320 Bluetec
You could always remove parts, have them powdercoated, and show off like I do with my Supra Notice how dirty my firewall and hoses are. This was without cleaning the engine, but powdercoating stays clean, just wipe off!
I don't recommend power washing. Just take simple green or another degreaser, and elbow grease. Spend a few hours in your engine bay (you did bring up this post, so I imagine you are willing to do that), and clean each component by hand. Even if you don't remove pieces, just use a screwdriver covered in cloth to get to those hard crevices/places. Next time you go to a MB meet, pop your hood and wow everyone!
Today's engines have those ugly plastic covers on them, so there's not much to do, so just hand clean all the pieces you can see, and u're good to go! You could even have the plastic cover painted which looks great.
PS, imagine powdercoating/polishing the supercharger on an AMG engine!!!
Notice how dirty my firewall and hoses are. This was without cleaning the engine, but powdercoating stays clean, just wipe off!I don't recommend power washing. Just take simple green or another degreaser, and elbow grease. Spend a few hours in your engine bay (you did bring up this post, so I imagine you are willing to do that), and clean each component by hand. Even if you don't remove pieces, just use a screwdriver covered in cloth to get to those hard crevices/places. Next time you go to a MB meet, pop your hood and wow everyone!
Today's engines have those ugly plastic covers on them, so there's not much to do, so just hand clean all the pieces you can see, and u're good to go! You could even have the plastic cover painted which looks great.
PS, imagine powdercoating/polishing the supercharger on an AMG engine!!!
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Joined: May 2003
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From: Long Island, New York
2018 E400 4matic Wagon
I've been hosing off the engine bay pretty much each time I wash the car for many years, and on many different cars, with no issues (I occasionally use soap as well). I do this starting from the day I buy the car. As a consequence, my engines always look like new until the day I sell the car. Not only does it look nice every time I open the hood to check the oil, etc., but when I'm selling the car, a gleaming engine bay definitely seals the deal.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,691
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W221 S600, W220 S55 AMG Kompressor, W124 300E, W140 S320, W210 E3204M W164 ML320 Bluetec
I've been hosing off the engine bay pretty much each time I wash the car for many years, and on many different cars, with no issues (I occasionally use soap as well). I do this starting from the day I buy the car. As a consequence, my engines always look like new until the day I sell the car. Not only does it look nice every time I open the hood to check the oil, etc., but when I'm selling the car, a gleaming engine bay definitely seals the deal.
I don't care to hose off the W123 300D but thought I would get some input before doing it to the W211.
