E-Class (W212) 2010 - 2016: E 350, E 550
Sponsored by:
Sponsored by: CARiD

[Help] Spark Plug bolt is stripped, how can I unloose them?

Old Jul 30, 2018 | 10:44 PM
  #1  
ND_eclass's Avatar
Thread Starter
Junior Member
 
Joined: Aug 2014
Posts: 59
Likes: 1
12 E-Class
[Help] Spark Plug bolt is stripped, how can I unloose them?



I believe a 6mm or a 1/4 works on this.
So I'm needing help, for some reason the bolts on the left(driver's side) bolts on the spark plug connectors seem to be stripped. I'm astonished at how the this could be as it should be the same size as the right side bolts. The right side(passenger's side) spark plug bolts came off without much effort. My question is that, I've tried to used a 12 pin 1/4 connector to turn them loose, but no avail. I'm looking for suggestions to getting them off given the tight space. Thank you in advance on responses! P.S. I can also post the PDF's of how to change the spark plugs without taking the manifold in w212 2012 and up.

Last edited by ND_eclass; Jul 30, 2018 at 10:47 PM. Reason: Add Pictures
Reply
Old Jul 30, 2018 | 10:50 PM
  #2  
ND_eclass's Avatar
Thread Starter
Junior Member
 
Joined: Aug 2014
Posts: 59
Likes: 1
12 E-Class
By the way, I feel like these screw heads are so soft as I mean, it's not like I kept trying to un-screw them. I'm a bit tired from this project, but I'm half ways, 3 plugs left.
Reply
Old Jul 31, 2018 | 12:07 AM
  #3  
JohnnyC's Avatar
MBWorld Fanatic!
10 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Sep 2014
Posts: 1,051
Likes: 216
From: LaLaLand
2015 GLK350 & 2020 C300
Well yeah they are soft, only 8.8 Grade. You will need to use extractor sockets or sometimes called turbo/twist sockets. They are helical impact sockets that you pound on and turn counter clockwise. If you don't use a E-torx socket you will mess up the head, this includes spline sockets. They are not for E-torx despite some places advertising it as interchangeable.
Reply
Old Aug 5, 2018 | 07:45 PM
  #4  
ND_eclass's Avatar
Thread Starter
Junior Member
 
Joined: Aug 2014
Posts: 59
Likes: 1
12 E-Class
So I tried using the socket "extractor." Out of all the hardware and auto speciality stores, only Walmart had them in stock online. Anyways, they still will not work unscrewing those rounded screws, and since it's a tight spot.. I'm just tempted to just be okay with changing only the three spark plugs on the passengers side of the car. Still, any suggestions that could work? I was thinking of using a "Dremel" but then again, the bolt is fastening a rubber spark plug socket.
Reply
Old Aug 5, 2018 | 08:45 PM
  #5  
JohnnyC's Avatar
MBWorld Fanatic!
10 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Sep 2014
Posts: 1,051
Likes: 216
From: LaLaLand
2015 GLK350 & 2020 C300
take off the air resonator plenum.
Reply
Old Aug 5, 2018 | 11:15 PM
  #6  
- Mover -'s Avatar
Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2017
Posts: 127
Likes: 31
E550
If you have room, try cutting a straight groove on the screw head so you could ratchet them off.
Reply

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

Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 04:43 AM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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-8
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
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE