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I'm living through this terrible issue right now with my 2012 E350. $11,000 worth of damage from the leak - even though I just had the 80,000 service that inspected for leaks.
Wow, that's terrible. What all was affected?
And, the dealer did the 80K service and failed to notice a problem?
Yup, I agree with you. I love my E550 and I plan on keeping it. It is worth it to repair rather than dump and get something else. Good luck
My gut says for the e550 tt an M278 reman long block job with wire harness and motor mounts would be around $16k-18k parts and labor at the MB dealer. For ghlkal and all, If you loved the car, would you pay that? Before just reacting as "no way!!" That MB reman block comes with a 4 yr/50k mile limited warranty which would make me take a longer look towards paying it if you are confident the rest of the car is in top shape and has been well maintained to the point you are extremely confident you can get at least 4 more years out of it without any more ghastly repairs as that $18k would average $4500 per year for 4 years - still cheaper than the expense of buying brand new over those 4 years. If you end up getting say 7 more years out of it, even if you had to throw in an extra grand a year average on top for some nominal repairs, you are still way ahead than buying new. If instead you buy another used one out of warranty, say for around $15-18k, you then still run the risk of a big bill or multiple big bills, maybe even shortly after purchase if bad luck arrives quicker than expected. If the reman dies under warranty, at least you're covered for 4 years per mbusa. The key to me in making that decision is the confidence you feel in what you have and the amintanence you had done on your car or do you want to roll the dice and go with the unknown.
Hey all, just changed my oil this weekend. I always have a good look around for anything suspicious. I noticed a small bit of oil leak at the bottom just at the front face of the engine. Looking from the top, and noting this issue I think possibly I have some oil seeping from around the camshaft magnet solenoid o-rings on one or more and running down. It's very hard to see anything with the big V8 and turbos shoe-horned in there, but I notice what seems to be a tiny bit of oil moisture on the engine around or below them. After some more research, I found the solenoid magnets are only about $46 each (there are 4 on M278) and are commonly replaced. The car is running fine with the exception of what I think was bad cheap gas from 7-11 one time recently that made it feel a little rough at idle, and set off an O2 sensor code which I reset and now seems fine after a couple of tanks of trusted Shell 93 octane. I found just the O-rings here, which are stated to be the same as OEM, part number 0169975045
Looks like a fairly simple task to remove and replace the o-ring seals. If I experience any further idle issues or codes I may replace the entire magnets part 276-156-07-90 which include the o-rings, or possibly investigate the O2 sensor(s) which send a code. This basically answers my original question here regarding preventative maintenance for this issue. Note, I'm at 98,xxx miles now.
They already cleaned the harness once... and the problems persist. I am comfortable hitting the control alt-delete.
I have obtained a sizable concession from the dealer to solve my problem in an un-compromised fashion. It's not quite the same level as outlined in the bulletin, but for me, it's close enough for horseshoes. Apparently, my argument with them, MB USA, and my service history carried some weight....
They are going to replace ALL the affected components: wiring harness, O2 sensors, ECU, and Camshaft sensors, and install new preventative pigtails, for a price at just over half of the original work order estimate. I know it's probably overkill, but given they've dried the harness once and problems persist and so I think the right course of action is a full re-boot. I've had nothing but great service from them and I trust their recommendation and respect their concession.
Besides, there is another dude with a CLS 550 from the similar born on date who took his to an independent mechanic who did the drain the harness procedure and pigtail install on the cheap... but now that guy (Rolondro) is experiencing a phantom turbo error message that so far has been impossible to pinpoint. I'm wondering if its possible its a poor signal from a half baked repair.... This uncertainty supports my decision to go with the dealer recommendation for full replacement. On the other hand, he could have bad turbos or cats.
Anyway... its all impossible to say for certain what is the best course of action. Bottom line is 1) I LOVE LOVE LOVE LOVE the TT V8 power of the E550, LOVE LOVE LOVE the e550 form factor, I love that my car massages my back as I drive, and I love getting progressively more bolstered as I pull more Gs in a turn. The car is un-compromised, and I'm happy to pay for un-compromised service to keep it in tip top shape. I'm going to roll the dice and continue on my original plan to drive it into the ground. Call me stupid in love. But whatever.
Still open to recommendations on whether I should replace the turbos while the engine is out. Car is at 96k miles. Also wondering what I should expect to pay for a swap of like for like for the turbos. It doesn't make sense that I should pay full price for turbos when given the value of remanufacturing my good ones. One the other hand, there is also something to be said for keeping TT's that have been flawless for 96k miles.... knock on wood.
One last comment before I sign off (and I'll report back one the final results)... after scouring the posts on this forum, most people here don't seem to keep their cars long enough to have a realistic opinion on actual reliability and maintenance costs. It's impossible to find for example reliable data on turbo longevity. Also, "reliability" threads seem to be packed with people boasting of things like "20k trouble free miles", or "I bought my car with 30k miles on it and am at 70k now and its as reliable as my old Honda..." What a joke. I guess what I'm starting to think is that most people wouldn't dream of owning a car like this out of warranty for the reasons I describe here. But what I hope (and believe) is that this car, properly maintained, will drive like a MB car drives, for as long as you properly maintain it. In other words, it's not a disposable box of metal, but rather a tank designed to provide decades of un-compromised experience with proper care and feeding. So if you have every five years a sizable $6k to $8k maintenance bill, you still are net neutral driving your beast of a car that is as satisfying as the first time you stepped on the twin turbo while getting your back rubbed and sides bolstered. You either pay to maintain your car in top shape, or you pay to replace a lesser box of metal every 8 years and incur the wrath of depreciation.
Two competing philosophies (I hope). For now, I'm going to roll the dice with the MB.
OP, thanks for your well-written and thoughtful follow up. I completely agree finding long-run data on reliability is very difficult because forums are not a representative sample and filled with errant posts of little use.
I wish you luck and agree with the prospect of keeping your car well-maintained. I would have the turbos rebuilt rather than replacing them. They should be serviceable items at a competent turbo rebuilder. Gives one some extra piece of mind when going through such an ordeal.
I just got the "news" last night and after googling it, this issue is wider spread and I'm wondering if it even goes to the M157 engines (E63, BIL owns one) - just finished posting in the GL forum, same issue with them... Here's my story:
We have a 2013 E550 Sedan and took it to the Dealer for an oil change and to check on a TSB for the Timing Chain Tensioners. Car has Only 36K miles on it and was bought through CarMax (and thankfully we bought the MaxCare warranty). SA calls me last night and says warranty Co approved Tensioner job. BUT, same oil leak that you all are discussing he tells me is happening to our car (no CEL yet). They've turned the claim in to MaxCare since the estimate to repair has gone north of $10,000, and they aren't done diagnosing. MaxCare is sending an inspector out before they will authorize repair. Don't see why they wouldn't as their warranty is more comprehensive than CPO's. However SA said if they don't cover it he'll try to get the Dealership and/or Mercedes to "help"... Are you kidding me???! I'm out of town and told the Wife that when the warranty is up the car goes.... And we absolutely Love this car , but we'd likely also Love an E63...
On Edit: this problem crosses a number of engines, yes including the M157 - so I guess our E63 will be a 4 liter (and I better check that out too!)
Last edited by diesel_dan; Dec 19, 2019 at 05:15 PM.
I decided to do a good de-grease on the front of my engine. It seems what I thought was oil leak around the cam adjusters was just a bit of old general engine grime. It all came off and it's been a week or two and no evidence of any oil leak around the cam adjusters or cam sensors on either side. Whatever the oil was down low that I saw when changing my oil must be coming from somewhere lower. Hopefully it could be just oil that leaked down when I changed the filter cartridge. I'll take the belly panels off and get up under for a good look soon. I also need to get transmission service done, it's overdue, so I'll have the shop look around for any leaks or issues when I do that.
I'm attaching a picture for clarification of the cam sensors and cam adjuster magnets on the M278 for clarification. I believe the older engines have the cam sensors on the front, but M278 has them at the top front of each cam. Other side is similar to this picture.
My 2012 E550 has just now been diagnosed with the exact same problem (all the way through to the O2 sensors) and I am on pins and needles about what the dealership/MB will do to address this well known problem since they seem to have not insisted dealers look for this issue when inspecting the car for periphery issues - such as the O2 sensor I just had replaced in September. If you have any advice on how to get the most coverage for a problem that MB clearly knows about, I would appreciate your input. I am hoping that RBM and MB will do the right thing on a CPO car with 35K miles on it.
I'm attaching a picture for clarification of the cam sensors and cam adjuster magnets on the M278 for clarification. I believe the older engines have the cam sensors on the front, but M278 has them at the top front of each cam. Other side is similar to this picture.
If still under CPO I'd definitely expect it to be fixed once it is showing problems or error codes.
To anyone who says they are having this issue on M278 engines, can you confirm that there is oil leaking from any of the cam sensors or magnets as in my picture above? Or what is the source of the oil leak?
Update on our oil in harness: SA called this morning to say Warranty Co. inspector is due out today. They don't see any reason claim will be denied. Interestingly he said they DO NOT install any pigtails to the cam sensors for this fix. He said the Part Number for the new harness is an updated number from what came on the car. He said they would be replacing entire harness and all 4 cam sensors and will check for any other downstream oil migration/sensor issues once motor is out. Probably going to be a great car for the next person as it is the highest optioned E550 Sedan I've ever seen. Looks like we will be giving a '15 E63S a go next, under warranty of course...
In the case of my '12 E550, it has been identified as the magnets. Dealer claims when magnets are all replaced, this will completely prevent oil into wiring harness from reoccurring. My vehicle was last in at RBM of Alpharetta (dealership) in late September and under 3K miles ago to replace an O2 Sensor. NOTHING was identified or reported about oil leakage into harness (or O2 sensor). Fast forward 90 days to mid-December and I had an Engine Light for a different O2 sensor and the dealership identifies oil had completely infiltrated the wiring harness and potentially corrupted ECU, O2 sensors, +++ (as oil was showing on the connectors). Nerve racking to put it mildly given the potential for a massive $12K+ repair bill. Called MB for help and no one from MB could provide answers to the following:
1) What could I, as a diligent consumer of an MB luxury car with under 36K miles, have done differently given NO visible signs of oil leakage?
2) How quickly does the oil pass through a wiring harness that should be impervious to liquids? (Obvious answer: under 3 mo./3K miles???)
3) What is MB doing to proactively address this issue given the potential damage/costs of rapidly spreading oil?
4) Why is MB not proactively replacing magnets or informing consumers of the issue and at least giving them the choice?
I believe these to be fair questions of a company that invests millions in commercials every 10 minutes during sports events, to garner customer experience.
MB Customer Advocacy has offered me a good will 15% off parts/service (or oh yeah, a great deal on a new car lease). MB -way to go all out to assist with a problem that has been so widely recognized by owners. I feel a bit like a patron that gets food poisoning from a restaurant and being offered a free meal next time.
Most MB repair shops are telling consumers to hold shop invoices in case/until a Class Action Suit forces a proper resolution from MB. Really wondering why it has to come to this and why MB is not more diligent in taking care of consumers that bought their product???
Thanks Jake - A bit of an update on ours as well: Warranty inspector showed up and said we didn't have MaxCare warranty! Ours is with another 3rd party that MaxCare farmed it out to (whole 'nuther story I won't go into). Finally heard from SA on Tuesday that claim is approved and now they get to work on it - supposed to be ready this Weds. He said they will be checking all sensors and things they couldn't get to when engine is out, but of the 4 injectors and ECU they've checked so far, oil hadn't gotten there. We may end up staying in the 550 for, well who knows how long, this will be fixed, the timing chain tensioners will be updated, the steering rack bolts and alignment done; since they're pulling the motor coolant will be changed and doing new engine mounts. I'm not so sure we wouldn't keep it out of warranty after all...
Oh, and the E63 we had shipped in to our local CarMax was an absolute disaster!
Maybe somebody's trying to tell us something...? Back on the harness leak at the cam sensor magnets: BIL has a '13 E63 and took it by his MB indy -- the guy said they check for that leak every time one of these cars comes in and they have cleaned up harnesses with zero returns (guessing they are catching them early). Said that the jumpers are not the fix for the problem, but I don't recall if BIL said the tech said it's the magnets...
On edit: meant to conclude that obviously this is a well known problem...
Last edited by diesel_dan; Jan 11, 2020 at 03:26 PM.
Mercedes cars have been leaking oil into wiring harnesses in this manner since at least the introduction of the M271 in the W203. My 2005 C230 had pigtails installed in 2008 to avoid this. It's crazy that after all that time this is still an issue. I haven't seen anything on the M276 yet, but since it is related to the M278 - I would not be surprised.
Hi. Just got back from dealer. Same crap. Oil contaminated everything. Huge bill to fix it. I have 2012 ML350 with M276 engine. Wonder if you got anything from MB USA.
Sorry to hear you have also be plagued by this known issue. MB started by offering me a small discount on a new vehicle. I found this akin to a restaurant offering a meal coupon to a patron that got food poisoning. They then offered 10% off parts and service as final. RBM's Service Manager, Craig Beauchamp, also provided a comparable discount on their work to help ease the situation. Because of the huge expenses associated with ripping and replacement of downstream parts (ECU, O2 Sensors, etc.), RBM's Service Manager and I jointly decided on a more conservative path forward - to clean the harness with detergent and dry it out, clean the connectors, replace the magnetic connectors with ones that will prevent future oil infiltration. RBM's Service Tech then put several hundred miles on the car to make sure other engine codes would not pop up. I accepted this knowing full well that I could experience death by a thousand cuts, throwing engine errors and replacing parts ongoing. After 3+ months (knock wood)...I have not thrown the engine light and am becoming more optimistic that the other components were not saturated by the oil leak. This process seems to have worked and cost me about $1.1K. Certainly a big invoice (that I one day hope to extract from Mercedes), but after toiling over the possibility of 10x that amount, it was a more palatable number. I give Craig Beauchamp of RBM North Alpharetta, GA huge kudos for making the best of this situation and offering a conservative 'lower initial cost' approach. He was empathetic, calm, and acted in every way as my advocate. Mercedes Benz on the other hand was difficult, unresponsive, unempathetic, and accepted no fault...instead trying to wash their hands of this situation. Hopefully you can find a reasonable approach for your situation, until the class action suit against MB gets announced.
Hi. Just got back from dealer. Same crap. Oil contaminated everything. Huge bill to fix it. I have 2012 ML350 with M276 engine. Wonder if you got anything from MB USA.
I know we did, but nothing on the up and up - it was only seeing what the warranty Co. ended up paying (versus our Estimate well north of $12K), and the SA saying they were "negotiating" with the warranty co. (and the dealership with MBUSA) on the prices of parts and labor... Dealer was the REAL hero in all of this: they gave us a loaner for a month, basically threw in the oil change and some other items we asked to have checked, and dealt with what turned out to be a difficult warranty company. Then again I think it makes a difference if you are a regular customer...
And we're going to take our chances and just keep the car when warranty runs out... Our first MB and we absolutely LOVE the car! I think the M278 should be more reliable than an M157 over the long haul as well...
Last edited by diesel_dan; May 6, 2020 at 09:28 PM.
My dealer won’t even talk to me. Independed MB mechanics won’t touch it because it will be none ending job and tons of $$$
wondering if any lawsuits already filed
Thanks for the heads up on this issue on the M278s. My indy noted it when he completed the PPI last May that it needed the updated CAMs, and I went ahead and had them changed out back in Feb. as a preventative measure, even though car has 13k on it. Just wanted to chime in and thank the forum! Now, I'm just monitoring for any turbo wastegate issues.. Took it in for B-service, and a CLS550 was in for the turbo issues. Didn't sound nice at all..
Last edited by mbvolvo92; May 8, 2020 at 09:46 PM.
Have the exact same issue and wanted to see what you ended up doing with your car. If you fixed and kept it if you've had any further problems.
No. I’m saying I have an m278 engine which was derived from the m273, and assembled with camshaft solenoids from a batch of solenoids shared between the m273 and m278 during the production transition. It is rumored btw that that those batches didn’t fully flush out until May of 2012.
Im also saying the core wiring connect on the m278 harness or the entire harness itself is either the same or not significantly different from the m273 harness. It’s certainly not designed to prevent downstream propagation oil leaks from leaky solenoids.
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, but we'd likely also Love an E63... 
Have the exact same issue, early model 2012 E350
