Engine Harness Wicking
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Junior Member
Joined: Dec 2025
Posts: 64
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From: Pittsburgh PA
2013 S550
Engine Harness Wicking
Hi! 2013 E 350. Does this have the cam sensor and phaser oil wikiing issue? Im new to the w212 format. I did the sacrificial harnesses on my W221 S class. Wondering if this needs them too. Thanks!
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Joined: Apr 2019
Posts: 11,811
Likes: 6,705
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Oily Harness Tips
MB has superseded newer longer sensors with slot openings from Continental that guarantee oil to wick straight through.
It's a reliability downgrade made sensitive to:
High engine heat
Low vehicle mileage (20kMi)
crankcase blow-by pressure
Down the line related damages are: Harness, Lambdas and ECU. Engine out repair necessary.
> 2 or 3 Pins: NO CONFUSION
MB provides 2-Pins harness extension for VVT Solenoid ("magnets") : hardly ever leak!
but does not have official pigtails for 3-Pins CPS : guaranteed leaker.
So you're left purchasing genuine knock-offs copies on eBay/Amz.
To means MB intend to keep this mature issue as-is with genuine leaky sensors and no-pigtails.
There may be ways to install lambda pigtails as used by leaky VAG cars.
Last edited by CaliBenzDriver; Jan 13, 2026 at 06:51 PM.
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Joined: Sep 2018
Posts: 14,655
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From: unbegrenzt
2017 GLE350 4MATIC
The pigtails are sacrificial. Using them protects the ECU and other downstream components. Eventually the pigtails will become saturated need to be replaced. Pigtails are better than no pigtails.
Out Of Control!!
Joined: Apr 2019
Posts: 11,811
Likes: 6,705
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
I would do:
-1- New CPS sensors + 3-Pins pigtails
-2- Inspect solenoids ("magnets") + 2-Pins pigtails
The key is to disable engine extreme heat soaks that are prematurely aging plastics & seals
-1- New CPS sensors + 3-Pins pigtails
-2- Inspect solenoids ("magnets") + 2-Pins pigtails
The key is to disable engine extreme heat soaks that are prematurely aging plastics & seals
Last edited by CaliBenzDriver; Jan 14, 2026 at 04:59 PM.
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From: SoCal
2020 E450 4matic wagon
Yes Sir, of course the W212 features the "10k oil in harness" issue to this day.
MB has superseded newer longer sensors with slot openings from Continental that guarantee oil to wick straight through.
It's a reliability downgrade made sensitive to:
High engine heat
Low vehicle mileage (20kMi)
crankcase blow-by pressure
Down the line related damages are: Harness, Lambdas and ECU. Engine out repair necessary.
> 2 or 3 Pins: NO CONFUSION
MB provides 2-Pins harness extension for VVT Solenoid ("magnets") : hardly ever leak!
but does not have official pigtails for 3-Pins CPS : guaranteed leaker.
So you're left purchasing genuine knock-offs copies on eBay/Amz.
To means MB intend to keep this mature issue as-is with genuine leaky sensors and no-pigtails.
MB has superseded newer longer sensors with slot openings from Continental that guarantee oil to wick straight through.
It's a reliability downgrade made sensitive to:
High engine heat
Low vehicle mileage (20kMi)
crankcase blow-by pressure
Down the line related damages are: Harness, Lambdas and ECU. Engine out repair necessary.
> 2 or 3 Pins: NO CONFUSION
MB provides 2-Pins harness extension for VVT Solenoid ("magnets") : hardly ever leak!
but does not have official pigtails for 3-Pins CPS : guaranteed leaker.
So you're left purchasing genuine knock-offs copies on eBay/Amz.
To means MB intend to keep this mature issue as-is with genuine leaky sensors and no-pigtails.
This is the gospel ...
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