correct. The dealer may be thinking incorrectly that the orings cause the leak that is the issue. While the orings MAY leak, that leak will not travel through the harness. Why? Because the wires are not in contact with the leak. The (seemingly all) plastic sensors that touch the block have pressure on them vs vacuum and when the heat cycling changes the fit of the electric pins running through the sensors, the oil will wick. If there is any argument here, it’s simply ignorance as it’s scientifically impossible to not wick which is why it’s so hard to fix. Capillary action can not be denied by the dealer management so ask to speak with someone with a mechanical or scientific background and not a business person that doesn’t understand entry level 8th grade physics. I’m not sure what this dealer is trying to deny for you but please visit another dealer as you are already on the losing path with your current choice.

 

Is that oil all over the connector when you unplugged it from the position sensor ?

Also what year make and model is this?

Reason I ask is because the dealership is insisting oil never leaked from the cam position sensors into the wiring. The dealer says its the cam magnets that were leaking which is why Mercedes made the pigtails to plug on the magnets.

When looking at the 3rd picture here, it appears to me oil is coating the connector which was unplugged from the cam position sensor but without being able to enlarge this pic, its a bit hard to say for sure.

 

Since all of us try to be brief, perhaps time to be precise with the language. I understood it at the first read because I have read about this topic 100+posts already. So, something along thiswill help to the new readers

Caveat: English is my 2nd language.

 

Both parts can leak. Please confirm that you understand this. Please explain this to your dealer, or find another dealer.

 

I'm currently dealing with the dealer who sold me the car, however I haven't found another dealer that will admit both are leaking. Seems like they are avoiding the issue. I have learned that Mercedes came up with a pigtail harness for the following engines and it only goes on the Cam Magnets. They didn't make one for the Cam Position Sensor because apparently no dealer will admit to that being a problem part on the M278. They've also said the pigtail that was made for this service campaign wasn't designed for the Cam Magnets on the M278. The dealer is exploring it with me at the moment. You must understand that the Dealer has more clout with Mercedes Benz engineering than drivers of used cars so I am working with them to get to the bottom of this since it happened to my car before they sold it to me. I simply want them to tell me how it won't happen again so we'll see where it goes. Why there was no recall for models beyond 2011 is a mystery to me.


Campaign No. 2012070002, September 2012

TO: ALL MERCEDES-BENZ CENTERS SUBJECT: Models 164, 171, 203, 204, 207, 209, 211, 212, 216, 219, 221, 230, 251, 463 Engines 272 and 273

Model Years 2005 - 2011

Retrofit Adapter Wiring Harness on Camshaft Adjustment Solenoids Revision Date Purpose A 9/12/12 Inclusion of Consequential Damage and Customer Reimbursement to Warranty information – 9/7/12 Initial Issue

This Service Campaign has been initiated because Daimler AG (DAG), the manufacturer of MercedesBenz vehicles, has determined that due to the settling properties of the seal, oil may leak from the camshaft adjustment solenoid. Dealers will retrofit four adapter harnesses onto the engine wiring harness as a precautionary measure at the next workshop visit Prior to performing this Service Campaign: ! Please check VMI to determine if the vehicle is involved in the Campaign and if it has been previously repaired. ! Please review the entire Service Campaign bulletin and follow the repair procedure exactly as described. Please note that Recall and Service Campaigns do not expire and may also be performed on a vehicle with a vehicle status indicator. Approximately 557,108 vehicles are affected.

 

https://mbworld.org/forums/e-class-w212/827474-sacrificial-cam-wiring-harness-e550-a2711500156-handle-oil-leakage-issue.html#post8445626

​​​​.i guess the link above is a hoax . If we keep looking through the different threads, several forum members have used the pigtails for the same purpose they were design. Then, engine number becomes irrelevant.

 

Changing part number is necessary when a part gets updated and made differently for sure, however I just had a dealer parts manager tell me Mercedes changes all part number near monthly to throw off aftermarket companies from taking parts sales away from Mercedes; its supposed to confuse everyone looking for parts online. This is why dealers will not give you part numbers over the phone. So based on that its not always a new design on the part when you see a new number.

 

How has been working?

 

If you search the forum, there is thorough investigation on the design of the position sensor, including dissecting the part and showing old and new. There have been revisions. I will take the sales person' s remark with a grain of salt, i.e. He has a conflict of interest?

If I find it again, I will update this post.

 

I wasn't saying new part numbers dont mean a revision took place, I was pointing out you cant go by a new number to determine the part has had an update because Mercedes changes numbers monthly to throw people off from buying the parts elsewhere besides dealers. This has been said by 3 different dealer part managers to me. They elaborated that Mercedes is trying to build out online parts sales and trying to intercept third party sellers. Changing part numbers constantly causes chaos for online sellers and buyers. It must be a headache to change part numbers so frequently but I understand their explanation for doing it because online sales are a cut throat business. Its made me shop with dealers more than once due to all the confusion of part numbers and thats the goal of Mercedes Benz. So it works when I buy from them.

 

I am not saying is not true, but I wonder how feasible that is. Any modification to the manufacturing process requires recertification, and time consuming, read $$, changing numbers on components falls in that category. Not only for making it happen, but also updating reliably the worldwide database. Changing specs just makes it more $$$.

Letting bean counters playing with engineering processes is looking for defects to happen.

 

This is rubbish. Especially so if it came from anyone who receives income from the retail auto establishment.

Part numbers from manufacturers change nearly exclusively because some characteristic of the part has changed. To wit: a revision.

 

I hope the revision ( new P/N ) is for product improvement and not cost cutting.

I think we should think this way for camshaft position sensor and phasor/magnet solenoid.

01. It is consumeable items. Set a mileage or years when you think its good to change without having yet a leak or while a super small leak.

I replaced my phasor/magnet solenoid when it was still healthy , simply out of fear it will leak and there is a new P/N, assumed revised better one.
I did not replace my cam pos sensor because the current P/N is the same as the one on my engine.

By year 10th if no leak on cam pos sensor, I would want to replace it anyway, take it as preventive and plastic will age at 10th year.
I do watch these sensors per oil change or 5,000KM or per 9 months, whichever sooner.
Seeing my 10th year rejuvenation list , cam pos sensor is cheap parts $$ wise and a simple DIY job.

I spent so much on engine* mounts ( *need workshop, my indie ) and tranny mount (DIY) because I am hyper sensitive when these mounts have passed its Creme La De Creme moment, which for me is approx 20,000KM.
So adding cam pos sensor and phasor/magnet solenoid as consumebale does make sense $$ savings wise and no need to loose sleep over it.

 

First off, thank you to everyone that has contributed to this thread. I never would have suspected this as an issue until problems started occurring.

I checked my cam sensors and did indeed find oil leaking from them. Also had the oil at the ECM connector pins.
I've cleaned the contaminated connectors with contact cleaner and am considering opening up the ECM to check the oil contamination inside. Has anyone opened one up? I'm concerned that a special sealant may be need during reassembly for a watertight seal but so as to not contaminate the electronics.

 

Here is a Bosch ECU being opened up. Ours is Bosch too, so sealant system would be very similar

 

Thanks for the video. I think I will try to look inside through the vent hole with a camera probe to begin with. I read somewhere that when they removed the vent plug, oil poured out!
Apparently their vehicle was running well for quite a while before issues starting popping up. This makes me wonder how tolerant ECU's are of engine oil.

It looks like some of the people that posted on this problem are still active members, so I assume you still own the vehicle.
What have you done to resolve the issue and how is your vehicle running?

 

Mine has no leak YET on both the cam pos sensors or phasor magnets.
I replaced all 4 phasor magnets for caution only sometime ago.
My car is very low mileage, only 37,000KM today, so less likely to leak but probably will leak as plastic will age.
By year 10th or 2024, the cam pos sensors all 4 I will replace, again out of caution.

 

Popped out the vent plug on the ECU to check for oil on the internal components...looked really clean!
FYI, I had as much oil on the ECU plugs as in the pictures in the first post.
Since the internal board looks clean, I'm not going to open the ECU. Every few months, I will check and clean the connectors, until the oil has migrated out of the wire harness.

Hope these pictures give anyone panicked by this, a sense of relief. From what I am finding out on professional forums, it takes a lot of oil to mess up the ECU. I have read that when the vent plug was removed from the ECU, oil would pour out!!
Hopefully our ECU's are also as resilient to the presence oil.

 

No oil getting through ...

 

So you have replaced all 4 cam pos sensors...right ?
Your phasor magnets all dry at connectors ?

 

Every few months, I will check and clean the connectors, until the oil has migrated out of the wire harness.

 

Mine is a 2016 GLC 43 (m276.823) which has started having this issue. I’m a bit confused though…
Is there a difference (besides the part number) between the camshaft solenoid A2761560490 intake and A2761560790 exhaust or are they interchangeable?

Nino

 

I just finished this on my biturbo M276. I ordered the parts from the dealership and they gave me 4x A2761560790 so I guess it doesn’t matter.

 

Just want to add.

Have a family member with M157 2015 ML 63 84k miles. Car was babied and garage kept for the past 7 years. Found oil in harness and ECU, Car started misfiring, dealer quoted 35k for new harness. I had 17 year Mercedes tech that wanted to look over the engine first before throwing a harness at the vehicle. Found cylinder 4 has cylinder was scoring and that cylinder is down about 10-15 psi on compression. Spark plug came out oily, so think that the oil made it to the ecu and possibly caused an injector issue on the cylinder.....?? Cylinder leak down is happening this evening. Trying to make this all make sense. Could oil in the harness lead to a scored cylinder wall? This car didn't have the oil pump solenoid removed so that might be a contributing factor as well?

With this info i checked out my personal car. 2015 ML63 with 28k miles on it and driver side cam position sensor that is right on top of the engine was covered in oil, no oil in the ECU so I am going to replace all the sensors. The magnets did have a spot of something in the connectors so I am going to do that as well.

I honestly think the we are on to something with the oil solenoid removal and that should help prevent the cylinder walls scoring because the engine is properly lubricated.

I am trying to make sense of the family car. Could the oil in the harness and making it to the ECU cause the injectors to leak or malfunction to cause the washing down of the cylinder?? Tech stated that the injectors weren't leaking. I am leaning to the oil solenoid is what caused the scoring, what i found with searching here is that the solenoid doesn't give the engine 60psi of oil pressure until 3500 rpm and that doesn't turn on the oil squirters until is sees 60psi.

Thank you everyone. REPLACE SENSORS AND MAGNETS!!!!!

 

Another forum member recently bought a damaged E350 (forgot the year). There was oil in the harness, and up to the ECU. The engine was still misfiring like crazy after cleaning everything. One thing he noticed (via XEntry if I recall correctly) was that one injector was pouring fuel into the cylinder compared the other 5. After compression test, the cylinder had no compression, basically dead.

He changed the engine, and he is now enjoying his "fixed vehicle".

My personal summary: ECU injection control mismanaged that injector (or the injector was busted). He did not summarized if he was able to reuse the ECU from the damaged engine onto the "used engine".

EDIT: here is the thread where the car ended with a "new used engine" ( https://mbworld.org/forums/e-class-w...fire-woes.html)