GLC Class (X253) Produced 2016-2022

Things to avoid when washing engine bay

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Aug 26, 2025 | 04:41 AM
  #1  
dadalook's Avatar
Thread Starter
Member
15 Year Member
Photogenic
Photoriffic
 
Joined: May 2007
Posts: 152
Likes: 8
Things to avoid when washing engine bay

Hello,

2020MY here. Going to get the car detailed soon. One of the service included is washing engine bay. They didn't mention whether it is power wash or hand wash with hose and brush. Is it save to do so either way? It sounds not ideal with all those electrical components getting wet potentially firing them.. should I skip or go for it?
Reply
Old Aug 26, 2025 | 09:15 PM
  #2  
DanD.'s Avatar
MBWorld Fanatic!
5 Year Member
 
Joined: Apr 2016
Posts: 1,124
Likes: 205
From: NW
2018 GLC 4MATIC
I've been doing it this way for many years:
1. Cover the alternator with a plastic bag.
2. Spray on degreaser (I really like the yellow one from Harbor Freight).
3. Let it sit for a few minutes.
4. Rinse with pressure washer using at least a 40-degree nozzle, from a distance of 1-2 meters -- never up close.
5. Repeat a few times as needed.

No brushes required. I usually do this every two years, and everything comes out clean with no electrical issues.
Reply
Old Aug 26, 2025 | 10:16 PM
  #3  
W205C43PFL's Avatar
MBWorld God!
 
Joined: Dec 2019
Posts: 32,514
Likes: 6,348
Originally Posted by dadalook
Hello,

2020MY here. Going to get the car detailed soon. One of the service included is washing engine bay. They didn't mention whether it is power wash or hand wash with hose and brush. Is it save to do so either way? It sounds not ideal with all those electrical components getting wet potentially firing them.. should I skip or go for it?
Originally Posted by DanD.
I've been doing it this way for many years:
1. Cover the alternator with a plastic bag.
2. Spray on degreaser (I really like the yellow one from Harbor Freight).
3. Let it sit for a few minutes.
4. Rinse with pressure washer using at least a 40-degree nozzle, from a distance of 1-2 meters -- never up close.
5. Repeat a few times as needed.

No brushes required. I usually do this every two years, and everything comes out clean with no electrical issues.
Good advice but genuine question, is it safer to not use any water instead? Are there some products that can act as water but won't damage electricals? I thought about using deionized water but of course the chances of it being ionized is high.
Reply
Old Aug 27, 2025 | 02:37 PM
  #4  
Mike0Ryan's Avatar
Newbie
Liked
 
Joined: Dec 2022
Posts: 11
Likes: 1
2019 GLC 300
I understand why you might think that deionized (i.e. H2O with impurities removed) water might be preferred because it does not (readily) conduct electricity, however I have to think that the water would become contaminated (and ionizable) as soon at it came into contact with the grime that you are trying to wash off.
Reply
Old Aug 27, 2025 | 06:31 PM
  #5  
W205C43PFL's Avatar
MBWorld God!
 
Joined: Dec 2019
Posts: 32,514
Likes: 6,348
Originally Posted by Mike0Ryan
I understand why you might think that deionized (i.e. H2O with impurities removed) water might be preferred because it does not (readily) conduct electricity, however I have to think that the water would become contaminated (and ionizable) as soon at it came into contact with the grime that you are trying to wash off.
Mhmm, that was what I thought.
Reply
Old Aug 28, 2025 | 09:45 PM
  #6  
sn202020's Avatar
Member
5 Year Member
Photogenic
Photoriffic
Liked
 
Joined: Jan 2020
Posts: 210
Likes: 79
From: Canada
2017 & 2022 GLC 300 4Matic
Well.. because my vehicle is not classic model car for showing under the hood at a festival,
no one look at my engine bay except myself or rarely mechanic.
I used to clean it twice with a degreaser spray and water, decades ago, but not anymore since, No benefit.

Only if the dirty spot needs to be cleaned for future diagnosis, like oil leak,
I use paper/cloth towel with alcohol spray or break cleaner. That's all.
Reply
Old Aug 29, 2025 | 12:05 PM
  #7  
mikapen's Avatar
MBWorld Fanatic!
15 Year Member
Shutterbug
Community Influencer
Community Favorite
 
Joined: Oct 2009
Posts: 7,018
Likes: 2,199
From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
I think that a clean engine bay makes a technician respect your car more. Maybe it inspires them to do a better job.
Maybe the inverse is more accurate, though - a dirty engine compartment shows that you don't care.

My engine bay is pretty tidy, with only dust and a bit of road spatter. It only takes a hose to make it look nice.
Reply
Old Aug 29, 2025 | 12:32 PM
  #8  
dadalook's Avatar
Thread Starter
Member
15 Year Member
Photogenic
Photoriffic
 
Joined: May 2007
Posts: 152
Likes: 8
Thanks all for the reply. I asked the detailer after the job and they said they power wash.. Glad I asked here beforehand.
Reply
MB World Stories

The Best of Mercedes & AMG

story-0

New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

 Verdad Gallardo
story-1

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-2

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-3

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-4

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-5

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-6

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-7

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-8

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-9

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
Old Aug 29, 2025 | 10:11 PM
  #9  
W205C43PFL's Avatar
MBWorld God!
 
Joined: Dec 2019
Posts: 32,514
Likes: 6,348
I am guessing those who live in sandy areas, it is probably not good to have that accumulated in the engine bay either, um.. harmful such as sand blasting?
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 03:05 PM.

story-0
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

Slideshow: Mercedes-AMG's new electric GT 4-Door Coupe trades combustion for software, synthetic noise, and more than 1,100 horsepower.

By Verdad Gallardo | 2026-05-20 20:08:15


VIEW MORE
story-1
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-2
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-3
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-4
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-5
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-6
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-7
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-8
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-9
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE