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I have seen a few claims that the M276 engine has the CPS and cam solenoid oil wicking problem that the M278 has. Does anyone know if this is a real issue? Assuming that it is, where can the wiring harness pigtails (extensions) be purchased?
I have seen a few claims that the M276 engine has the CPS and cam solenoid oil wicking problem that the M278 has. Does anyone know if this is a real issue? Assuming that it is, where can the wiring harness pigtails (extensions) be purchased?
Sorry, but those are not claims, They are a fact for all the VVT engines, any brand. It seems the MB engines have been more prone to that. Hotter engines damaging plastics?
The harness is coded with A271xxx, which indicates they were associated with the M271 engine first. Because the connector is common MB 2pin, they can be reused in other models, they have been used in the M271, 272, 273, 276, 278, ....
Since the real problem are the o-rings on these sensors, does anyone know where they can be purchased. I've looked on multiple sites and didn't find any reference to them.
Since the real problem are the o-rings on these sensors, does anyone know where they can be purchased. I've looked on multiple sites and didn't find any reference to them.
The o ring are, basically, a maintenance item like any oring.
However, oil migration is not because of them, but because the plastic cracks/porous and oil migrates through the sensor casing into the wiring.
It is a silent failure, you do not see it, until boom, you start having misfires, rough idling, etc.
If oil makes it to the ECU, you will be facing $$$ in repairs
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by CaliBenzDriver
These are only sacrificial harnesses, not any done-deal cure.
So you may need to keep replacing pigtails until you replace seasoned plastic sensors
Ya know, I did order a set of 8 harnesses just to have on hand to replace the ones already on the car if I see oil has migrated through one or more of them. Who knows if they will be available or at this price a year or more from now. I have two M276 engines to maintain.
A 2014 E350 will have a M276 engine, which is also known to have this issue.
Basically, all 4 Camshaft solenoids and all 4 Camshaft hall sensors are prone to oil leakage into the wiring loom. This oil will spread over time (capillary action) into the ECU connector, from which point it will further creep into the rest of your loom. If not caught in time, it's a new loom, ECU cleaning (or replacement) and cleaning / renewals of affected sensors.
To reduce the risk, you can install 8 pigtail wires (see
) on the offending solenoids and sensors. These pigtails reduce the risk of oil spreading through the loom and into the ECU. Installation is pretty straightforward, if you remove your intake manifold you can easily get to all 8 connectors.
Of course, even when using these pigtails, you still have to keep an eye out for any oil leaks itself. If a sensor or solenoid starts leaking, replace the offending part, and replace (or clean) the pigtail wire.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
The pigtails are considered sacrificial wiring extensions. Mercedes actually makes the extension harnesses for the solenoids (magnets), but not the CPS. But, for the half the price of the Mercedes harnesses, you can get all 8 on
I have a 2014 E350 wagon. Am I supposed to know about this? What is this issue?
sorry for being a noob about this.
Look at the front of your engine and inspect for traces of oil. If you are underneath, it will wick down there too. These engines are notorious for having leaky timing covers. Mine had 27K when I bought it and it had already been leaking for likely a year. Once resealed, they have been bone dry and she now has over 60K. While you are looking, remove the top front engine cover and inspect all your cam sensors for oil.
What's the difficulty of these fixes for those of us not quite so DIY inclined? Doesn't seem too hard but ...
It's not a hard repair at all...all you need to know is how to open the hood and have a set of pigtails on hand to connect. Here is a YT video which explains to procedure...note it is an S class but the principle is the same. Easy peasy....😉
The pigtails are considered sacrificial wiring extensions. Mercedes actually makes the extension harnesses for the solenoids (magnets), but not the CPS. But, for the half the price of the Mercedes harnesses, you can get all 8 on Amazon. (See my link above or click on Amazon here.)
I've got a M272 motor and have the pigtails installed on the magnets and position sensors. I treated them as pre-emptive maintenance... replaced all the magnets and position sensors @100k miles. Bought everything on FCP Euro and when my wagon hits 200K, I'll warrantee them on FCP Euro...
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by hecdog
I just want to say thank you to all who replied to my noob question. I came from a w211 and hadn’t heard of this issue.
I will remove the front engine plastic cover and take a look tomorrow.
don’t know how to take the intake manifold off but you seemed to imply it was easy. I do wrench a bit, so hopefully it’s not beyond my skill set.
cheers!
Unfortunately, removing the intake manifold on the M276 is a pain in the butt, but doable, and necessary when changing spark plugs. You just need to pay attention to what you are doing and take your time. There's no special or exotic tools needed. Here's a video that shows what needs to be done.
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. 3 M276 engines around here.
