M177 Engine wiring harness a oil sucker ?
Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
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From: Keep it simple - keep it OEM
AMG C63s Coupe
M177 Engine wiring harness a oil sucker ?
Hello friends of M177 (LS1),
I saw a video where was reported that engine oil
could get into the engine wiring harness, which in the worst case
could cause significant problems.I suspect that older vehicles with potentially higher mileage
are affected; I have heard of it times ago ( more M156 etc than M177 - no panic!)
A solution was also presented, called „oil stop cables“.
(short cable pieces with plugs).
It was said that Mercedes would also offer something like that. (Special for M177 i dont know)
The culprits are likely the sensors,
etc. on the cylinder head.
The oil is supposedly getting into the cables
via these components.
I like to get to the bottom of things,
have a few questions for you.
Are you familiar with this problem,
or were you affected? (M177 LS1)
How does the advertised solution technically work?
(A piece of cable with a plug, is no explanation for me).
If the oil comes from sensors is there
no better solution to seal them constructive
more ?
Have this sensors ever get a update or other partnumber ?
I know that i can ask by @ MB, Supplier, Guy Xy … but i know based on experience nothing comes back.
I saw a video where was reported that engine oil
could get into the engine wiring harness, which in the worst case
could cause significant problems.I suspect that older vehicles with potentially higher mileage
are affected; I have heard of it times ago ( more M156 etc than M177 - no panic!)
A solution was also presented, called „oil stop cables“.
(short cable pieces with plugs).
It was said that Mercedes would also offer something like that. (Special for M177 i dont know)
The culprits are likely the sensors,
etc. on the cylinder head.
The oil is supposedly getting into the cables
via these components.
I like to get to the bottom of things,
have a few questions for you.
Are you familiar with this problem,
or were you affected? (M177 LS1)
How does the advertised solution technically work?
(A piece of cable with a plug, is no explanation for me).
If the oil comes from sensors is there
no better solution to seal them constructive
more ?
Have this sensors ever get a update or other partnumber ?
I know that i can ask by @ MB, Supplier, Guy Xy … but i know based on experience nothing comes back.
Last edited by C63s_Jack; Jan 18, 2026 at 05:10 AM.
Member
Joined: Mar 2022
Posts: 98
Likes: 19
From: Vancouver
C63 MY15
Unsure if it’s an issue on M177 - from what I gather the sacrificial pigtail / harness are the same for all MB models or at least most of them.
The additional cable/harness I assume works by adding in a break in the wiring look so the oil cannot wick up into it.
did you find out any info?
The additional cable/harness I assume works by adding in a break in the wiring look so the oil cannot wick up into it.
did you find out any info?
Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
Likes: 37
From: Keep it simple - keep it OEM
AMG C63s Coupe
Yes i am also unsure about this issue on a M177 or whether it is so pronounced.
I know only one person personally who had that on M177 pfl.
I dont know how this osc-works.
The real question is whether, in such a case, it wouldn't be more sensible to replace
the leaking sensor.
Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
Likes: 37
From: Keep it simple - keep it OEM
AMG C63s Coupe
Unsure if it’s an issue on M177 - from what I gather the sacrificial pigtail / harness are the same for all MB models or at least most of them.
The additional cable/harness I assume works by adding in a break in the wiring look so the oil cannot wick up into it.
did you find out any info?
The additional cable/harness I assume works by adding in a break in the wiring look so the oil cannot wick up into it.
did you find out any info?
( in the moment ) it souds the M177 is not so affected by that. I found no further clues and I really tried to find out something. Maybe a hoax.
Yes the the M156 ( and others have this problem) - i know.
Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
Likes: 37
From: Keep it simple - keep it OEM
AMG C63s Coupe
No topic for the 63s 205 but all the others with this cable oilsucker problem.
I was thinking about a solution to fix.
I have done such build a car connector / car wiring harness years ago.
Have all this tools (crimping pliers etc)
and things too that are needed.
Maybe a solution - why not solder the copper conductor ( from cable) before crimping them ?
Normaly you dont do this (solder) when you crimp.
As I understand it, the oil comes through these open copper conductors
into cable along untill it says hello engine control unit
here i am many years later.
The question is would solder the copper condictor
before crimping (+ something like Dirko HT on the end where cable isolation starts) fix this problem ?
I was thinking about a solution to fix.
I have done such build a car connector / car wiring harness years ago.
Have all this tools (crimping pliers etc)
and things too that are needed.
Maybe a solution - why not solder the copper conductor ( from cable) before crimping them ?
Normaly you dont do this (solder) when you crimp.
As I understand it, the oil comes through these open copper conductors
into cable along untill it says hello engine control unit
here i am many years later.
The question is would solder the copper condictor
before crimping (+ something like Dirko HT on the end where cable isolation starts) fix this problem ?
Last edited by C63s_Jack; Feb 15, 2026 at 07:37 AM.
Member
Joined: Mar 2022
Posts: 98
Likes: 19
From: Vancouver
C63 MY15
MB themselves sell a cable to fix this - could be easier/cheaper than sourcing connectors yourself.
Please double check fitment - but this is what I saw:
https://www.fcpeuro.com/products/mer...500156#fitment
Please double check fitment - but this is what I saw:
https://www.fcpeuro.com/products/mer...500156#fitment
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Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
Likes: 37
From: Keep it simple - keep it OEM
AMG C63s Coupe
I a lot of work. But some of these cars get a rebuild (restore) with a new made engine harness ( custom & handmade). There you can do it. A old oily fu*kt up harnes i would not do this any more. the plastic conectors you can reuse … needed is only the silver metal clip ( i dont know the exactly word in english).
Last edited by C63s_Jack; Feb 16, 2026 at 05:44 AM.
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Thread Starter
Senior Member
Joined: Dec 2025
Posts: 425
Likes: 37
From: Keep it simple - keep it OEM
AMG C63s Coupe
MB themselves sell a cable to fix this - could be easier/cheaper than sourcing connectors yourself.
Please double check fitment - but this is what I saw:
https://www.fcpeuro.com/products/mer...500156#fitment
Please double check fitment - but this is what I saw:
https://www.fcpeuro.com/products/mer...500156#fitment
Last edited by C63s_Jack; Feb 19, 2026 at 02:09 AM.
