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Couch,
I am not replacing the small camshaft position sensors, I only have the supposedly will-leak electromagnetic cam phasor based on its part number.
Very helpful thread here. My indy shop just discovered oil in my wiring harness during spark plug replacement this week. The oil was originally found in the front two spark plug harnesses while changing the plugs. The shop claimed they did not find it in any of the other spark plug harnesses. I checked the cam sensor and solonoid harnesses when I got home and have oil in the camshaft sensor harnesses, but did not see it in the solonoid/magnet harnesses.
My indy shop recommended full front timing seals, covers, gasket replacements to solve this to the tune of $4k, but this now seems excessive after reading this thread and doing some research.
I'm curious what the results have been for those who have installed pigtails or replaced the cam sensors. Did this solve your problem?
I checked my ECU yesterday too and found oil there... thankfully no check engine codes, misfires, or issues with driving the car at all. See photos below.
Last edited by MickNotTheMouse; 11-24-2021 at 02:07 PM.
My sensors have not leaked anymore. I did cleaned my ECU with PC contact cleaner, and a Qtip. Oil penetration in your case is on the verge. I would perform an engine rinse down with Sonax engine cleaner. Is what MB uses to clean engines when looking for oil leaks with a dye, and they don't want old oil to interfere. Is also good on plastics.
Make sure that when you are drying, you first air dry. If you have access to a lift make sure you clean the bottom after removing the cover. A lot of grime will come down.
I replaced the electro-magnets (camshaft) as well as the sensors.
I still find this weird since I have been told by 2 different dealers that 2011 and beyond are not affected by the camshaft sensor leaks...regardless I have a 2011 NA 550 4M 0 and I still put the pig tales in just to be safe...seems like its still needed going forward too?
I still find this weird since I have been told by 2 different dealers that 2011 and beyond are not affected by the camshaft sensor leaks...regardless I have a 2011 NA 550 4M 0 and I still put the pig tales in just to be safe...seems like its still needed going forward too?
Those dealers would be wrong - my 2012 E550 had leaky cam sensors and many others beyond 2012 have reported the same. I agree the pigtails (if you can get them) are cheap insurance.
I'm sorry, I was under the impression that this is a V8 issue. Does it affect the 6 cylinder too? Referencing the comment that anything until late 2016 build will leak.
I'm sorry, I was under the impression that this is a V8 issue. Does it affect the 6 cylinder too? Referencing the comment that anything until late 2016 build will leak.
Yes, 4, 6 and 8 cylinder engines can be affected. The main culprit is the camshaft position sensor, a parts bin commodity that was used across a number of MB engines. M274 4-cylinder, M276 6-cylinder and M278 8-cylinder, potentially more engines. From memory there have been reports on this side of the camshaft solenoids leaking, in addition to the camshaft position sensors.
So.... I did my 4 x cam phasor magnet replacement. finally
Check :
01. All 4 camshaft position sensors are clean at its connector side, no leak.
02. All 4 cam phasor magnet also clean, no oil leak at connectors. I am keeeping the old 4 units as spare.
While at it I did some other cleaning and preventive maintenance.
S-Prihadi, I'll be interested to hear how you make out with the swap. I just changed my sensors yesterday after discovering that the two right bank sensors had been leaking. The cam adjusters have not been leaking so I will monitor for now, and replace at some point.
I had a good look at one of the leaky sensors with a lighted magnifier, no obvious signs of defects that could cause leakage. I'm going to bring it into work and take a closer look under a scope.
The interesting thing is the old sensors I had pulled out. They are made by Continental, part number A276905. All 4 have a stamping of "01 43" , could be a cryptic date code. I'm guessing these are not the original OEM sensors? If not, I'm surprised that two of them are leaking!
It seems my cam position sensors are different type than yours C67
I was also cleaning my aftercooler and oil leak trace from the camshaft ( also top part time chain ) window, so if only 4 of cam phasor magnets, below in red is what need to be removed.
Loose a bit of coolant for the turbo, as the turbo coolant recovery bottle must be removed.
I also took my slow sweet time .... . I am sure in 2 hours most can complete it for a M276 3.0 TT
Access the most right side cam phasor magnet ( bank 1 ) lowest point baby torx screw is the why some components removal on Bank 1 is inevitable.
Left Bank (B2) no need to remove anything.
I also was experimenting on re-tightening all screws for the camshaft/timing chain window to stop the famous leaky zone. I was adviced by my indie workshop.
Below oil leak trace is also seems to be from the cam phasor magnet o-ring too.
My indie workshop is quite right. It does make sense.
The original mercedes torx screws get a little kind-of loctite thread locker from factory after they apply the sealant and torqued down to 5 Nm.
So what I did was break the thread locker and do extra 90 degrees tightening of which the value is only 7 Nm ending at 90 degrees.
After breaking the thread-locker, the screw spin easy and not even 5Nm value. So my theory is below :
I think what happened is, due to factory speed of assembling these engines, their ultra thin layer of sealant application, the sealant shrank over time.
I recalled if I do a sealant type gasketing, I would wait for the sealant to become a tiny bit tacky and not messy-to-touch and only when so, I then torqued down the screws.
This is how I seal all underwater fittings on yachts too and it never failed.
In red are those are the ones I re-tightened on both banks.
I also had a super minor coolant drops escape when engine is driven hard. I loose less than 2cc for sure, no level drop at bottle due to too small a loss.... but I hate it .
It is from the turbo coolant recovery bottle bottom hose connection. It is a plastic quick coupler with an 0-ring inside it.
I forgot to get a new o-ring from MB, but I gave it a good cleaning.
First time I seen this super duper small leak is at the race track fun drive in 2020 and now it is the Jakarta-Bali-Jakarta run 2021.
Never ever happened in between if only regular city driving as I can't race the engine wildly in the city over and over for hours.
It seems my cam position sensors are different type than yours C67
S-Prihadi, yes it appears that way. The sensor body after the o-ring seems to be longer on my cam sensors. I have not compared part numbers but they are definitely not the same sensor. Interesting.
Does the 2013 S550 need the pigtails just to be safe? It has M278 engine.
I replaced all 4 sensors and magnets last spring and did not see any oil in the plugs. But if they made pigtails to fit mine, I'd like to get them just to be on the safe side. So far I'm not getting any answers from dealers.
Does the 2013 S550 need the pigtails just to be safe? It has M278 engine.
I replaced all 4 sensors and magnets last spring and did not see any oil in the plugs. But if they made pigtails to fit mine, I'd like to get them just to be on the safe side. So far I'm not getting any answers from dealers.
Dealers don’t know and don’t care.
Pigtails are cheap, so you could buy one and see if it fits your vehicle. If it does, buy the remaining three.
It's in the harness already and made it way into the ECU. The car is running with no problems, but now it's only a matter of time. Right connector top left pin and 9th pin.
Get this swapped today guys.
My guy I have the same amount of oil weepage, everytime I change my oil, I clean my connections and ECU with Sensitive electronics cleaner, it takes 15-30 minutes and is very satisfying. I think the oil can cause high electrical resistance and fuses to blow though.
Just got off phone with a dealership about this issue of oil seepage from the cam magnets and cam sensors. He looked up my VIN and saw the service records that shows the previous owner went through this and the entire harness and a list of other things were replaced due to oil seepage, it was a pretty big deal because of the list of parts it affected. The car is a 2013 S550 so beware of this issue and know that when I bought it, it had 68,000 miles on it which means it happened at pretty low mileage. I bought this car from the same dealership that sold the car new and maintained it until they sold it to me and they said nothing to me about this. Last May when I replaced the magnets and sensors out of precaution after hearing about this problem there was no sign of oil seepage on the wire connector plugs so it can only leave one to wonder if its going to happen again. These dealerships are fixing these problems with Band-Aids and then pawning them off to people on the secondary ownership market which shouldn't be allowed to happen.
My guy I have the same amount of oil weepage, everytime I change my oil, I clean my connections and ECU with Sensitive electronics cleaner, it takes 15-30 minutes and is very satisfying. I think the oil can cause high electrical resistance and fuses to blow though.
Have you swapped your sensors and installed the pigtails?
Does the 2013 S550 need the pigtails just to be safe? It has M278 engine.
Did you try a pigtail? I would think it would fit since it's the same M278 engine ...
Originally Posted by s550hollywood
These dealerships are fixing these problems with Band-Aids and then pawning them off to people on the secondary ownership market which shouldn't be allowed to happen.
Yup, that stinks. The bigger issue is that MB should acknowledge the issue and assist owners in fixing it.
Question for anyone who has dealt with oil leaking from one of these parts into the electrical connector attached to it which leads to destroying the entire engine harness. There's a current debate with senior management of a large Mercedes dealership who is saying the oil was only leaking from the cam magnet and it was not the cam position sensor that was leaking oil into the harness. Please list your answer and please include what engine you have had this problem on.
Is the oil leaking from this part? I'll call this part Cam Magnet
Or is oil leaking from this part?I'll call this Cam Position Sensor
Last edited by s550hollywood; 11-07-2022 at 09:18 PM.
Question for anyone who has dealt with oil leaking from one of these parts into the electrical connector attached to it which leads to destroying the entire engine harness. There's a current debate with senior management of a large Mercedes dealership who is saying the oil was only leaking from the cam magnet and it was not the cam position sensor that was leaking oil into the harness. Please list your answer and please include what engine you have had this problem on.
Is the oil leaking from this part? I'll call this part Cam Magnet
Or is oil leaking from this part?I'll call this Cam Position Sensor
Both parts, position sensor and magnet, are known to leak.
08-02-2021, 08:52 AM
. I am sure in 2 hours most can complete it for a M276 3.0 TT
