Hi everyone, fairly new to the forum. I dropped my CLS 550 (2012) off at the dealership for a Service A and a new set of tires. Car is at 73k miles, second owner from 22k miles originally. I know it's a performance motor and there is high pressure, etc., they cost money to maintain obviously, it's not really about the money, it's about the issue, how do I verify and should I do the work myself? I do everything myself except for deep motor work (camshafts, cylinders, etc.). Seals feel do-able but ultimately, I'm kind of surprised by this news. Dealership came back and said the following:

1. Front covers are leaking down to alternator and the A/C compressor. This is priority because oil can damage these components:

2. The oil pan is leaking from the seal:



3. Rear main seal, inside housing. Caps allegedly covered in oil and used a tool camera in there to see oil on housing...?:



4. Oil cooler leak, hidden they said, no picture. Say it's leaking. I've heard stories of a large nut or seal beneath or possibly three seals to this thing and they can leak?

Overall very bad news. They're quoting:

• Front Covers $1,460
• Rear Main seal $2,960
• Oil Pan Re-Seal $3,930
• Oil Cooler Seal $1,190

Almost $10k overall in repairs. Ultimately, I'm just grounding myself and assessing right now. I do a lot of work myself, have extensive tooling and investment in caring for my own vehicles. For this car, I've done brakes, rotors, brake fluid flushes, batteries (aux and main), spark plugs, coolant, engine air filters, belts, etc. These obviously get a little more involved in disassembly but overall, I'm pooling resources, asking around and seeing what the consensus is. When I originally bought the vehicle, Benz mechanics said this thing is built like a bull, may have to do air suspension living in New England roads around 100k miles and that can have a heavy cost but we're talking a $90k car new, built for performance, I don't beat on it...I'm surprised this thing is leaking like a Siv.

That aside, I'm assume these problems exist. What I'm trying to assess is have others done this work themselves, do they advise it? Are there any very useful resources for these seal adventures? Is this normal for these cars, have people owned or seen a lot of this. I can understand the cost (it doesn't surprise me and I knew buying this vehicle it has a higher maintenance cost associated with performance), but for Benz German engineering...I am a little surprised at how many leaks they're claiming...like really?

Anyway, I figured it's time to hit up the forums, see what people's advise is. I love the car...it's my favorite vehicle, best I've ever owned. I love this model...I know many would probably say that's in the trash but I have to consider all avenues because I may attempt the work myself and keep her. I don't really want to see her go, but alas asking around, seeking advice from you great folks here and seeing realistically what I should do or consider is paramount right now while I assess, I coped the day I bought it LOL.

Thanks!

 

Find a good independent mercedes mechanic. Don't pay stealership prices. You will surprised at the price difference.

https://www.benzshops.com/benzshops/massachusetts/

 

I have a 2014. Had oil leaking from the cam magnets and cam position sensors on the front of the engine. Had to change out three of each one of them. I am at only 53k miles. Sorry about the extent of your oil leakage but I guess this is one of the realities of this engine. And I do not beat on this car at all.

BTW our 2015 GLK with the M276 V6 had similar issues. So this era of Benz engines have known weaknesses.

 

I've noticed a little seeping around the cam sensor covers on my '13 - it looks like DIY. Did you do it yourself?

 

Appreciate everyone's input. I spoke with a separate independent shop source certified in AMG, SL and upper models. He said these leaks are a reality of their performance line. He says generally, most people just drive with these leaks if sensors or oil pressure is not an issue and usually they go the life of the vehicle without ever becoming a "major" issue triggering sensors and needing real attention. He defined that "life of vehicle" as at least until someone is ready to trade in for a new AMG or it's old enough in miles that they're ready for a new one. He said it's really 50/50. He said the motor itself is fine to 200K easily and a brick house in a wind tunnel but doesn't mean a shingle can't fall off LOL. I guess these leaks are a reality for performance but it doesn't shock me.

As for the leaks themselves, the rear main and oil pan (found out we talking upper, have to drop whole sub-assembly to access...realize price now...major job to get to) are very minor and not an immediate concern at all. The oil cooler I'm evaluating...it's tucked in the lower front but considering the cooler, feed line and return line, I believe I can get to these and handle them myself. I'm still waiting to hear from the tech on exactly what was leaking on this system but I suspect the items are affordable enough that I might whack the majority of the system and reseal it all. The front covers are 100% DIY. Take off engine filters, take off intake feed and some front architecture on the motor where the caps and cam sensors are and you just do it yourself. Oil should be drained to the base but if you just drove it, probably let the motor cool and oil settle before taking covers off certainly.

My understanding on many of these leak seals after discussing and looking around is that Benz engineering has extremely precision machined interfaces. As such, they don't believe gaskets are needed, only sealant because it's such a precision machined mate. Talking to the AMG expert, this seems highly debated from whether it should still have one or not, aluminum or block thermal expansion and cooling constantly. Some also discuss opting into other sealants non-Benz that they say provide a more life long seal but I'm pretty big on staying OEM provider recommendation if I'm not intending to modify the motor and performance. Designed that way for a reason and to me...these are just a necessary evil in performance, turbo's, high pressure, etc. Cant exactly be shocked right...but I do wonder what improvements have been made nowadays and if still machined or sealed the same way. I bought the seal kit for the front, bolts are color coded and one time use due to Loctite grade and disturbing the seal. New kit and parts for front covers was only $224 or so. Bought engine filters to do while disassembling and new main battery failing slightly. Spent like $650. I'll evaluate the cooler and then if I feel I can access which I think I can, buy a kit for that.

Finally, the rear main and upper pan seal are highly subjective. AMG expert says you could drive the whole life to 200K miles and they never evolve to a major issue or they could...says most just drive them even in AMG and they never develop to major most of the time. Depends on income, intended life of the vehicle....your baby and keeping it...will you ever rebuild her...trade her for a new model. He said if I do have the work done, pulling the motor while sounding excessive can save six hours of labor on the jobs as access and they have overlapping labor. No need to ever do pump or anything else while in there he said, maybe mounts since disturbed and they can rattle long term, do them while in there sort of deal and affordable enough that it makes sense. It is a tight spot underneath even on a lift. Not a job I would want to tackle by any stretch of imagination. It's very much a major job. He said if I do have that work done, likely the seals will last until north of 160K miles or when I'm finally seeing the tail end of her life, so it's really a personal decision based on your finances and intended use of the vehicle. That said, she's my baby...I LOVE this model. My favorite car I've ever owned, so I will likely hard save and put $5-6k aside over the next few months and just get the rear main and upper pan done because I have zero intention of trading her in at only 74k miles, I want to save her. The front fascia of 2012-2014 CLS 550 has never been topped IMHO. This model looked so good and when I went to college I said, "God I want that car!" LOL, so I will likely soak it and take care of my baby. I won't look forward to the day she hits high mileage but Benz has several years to that extent to wow me with something else but all these flat screens and EV don't do a thing for me...gages, buttons, power...engineering at its finest to me being in engineering myself. Screens, lights and lack of sound in EV don't do anything for me personally. Doesn't say luxury to me you know! Like why do people buy Rolex, Breighling, and high end watches? The craftsmanship, gears...a nice time piece and a piece of engineered beauty. Wish Benz would think about that with some of the stuff they make lately or at least give me the option even if it costs more. Let me pay for my stubbornness LOL.

Thanks everyone and I'll report back if I learn any tricks or real important info along the way for future readers!

 

did you get oil leaks fixed? I'm in the same boat with my 2014 CLS550 4matic only 66k miles. I have 3 more days to decide on keeping it, it runs great lots of power, and looks awesome I named it white ghost. Let know what you've had done thanks

 

Hi Flizsr917, getting back to you a bit late but figured you may appreciate some information on the results or future readers all the same. I did seek out an independent certified shop. I spoke with a gentleman who was vetted in SL63 AMG series, AMG GT and high end lines. My understanding after much research and discussion is that these types of oil leaks exhibit with all performance models. Part of this is machine precision seals and the other is lack of gaskets in vote of lubricant seals only, thermal expansion continuously, etc. It's an open debate but regardless of the fact, it came down to a 50/50 split for leaks detected. They resulted in the following:

• Rear Main Seal & Upper Pan Leaks - these on mine are both minor. The car really does have a bell and whistle for everything. These leaks being a concern for wear and tear on the motor, safety to drive, etc....the car has sensors for all of them, mainly oil pressure. The understanding I have is that all performance vehicles from Mercedes due to pressure lubricant machine precision seals have and at some point exhibit these leaks. The experts I discussed with said these are always minor and generally never an issue to drive on. They said they have customers with AMG vehicles and nearly all of them just drive them day to day no problem (even the dealership came clean with me and voiced the same opinion saying they have friends with AMG's and they do the same). They said if they ever evolved to being a leak that is an actual concern, the car will tell you and you'll know because oil level or pressure indicators will tell you there is a problem. Unless that were to happen, I was instructed it's perfectly fine to drive this way and it's expected with performance motors of this caliber. While it sounds scary, evaluating the leaks myself...they don't seem so harmful. I prefer they were perfect seals but what maintains perfection in this kind of performance, it's all subject to wear and tear. It's a double edge blade...and depends on the owner. If you upgrade every few years, perhaps you upgrade sooner. I myself and what likely is the answer you're looking for am planning to keep my CLS550 2012 until the day she dies. I love this model and Benz has yet to make another model I like more. I originally was instructed and this holds true today, that the motor and turbos are built like a brick **** house and will go to 200-220K miles easy. As such, I was instructed as follows...fixing these two leaks is optional. More than likely, I can drive the life of the car until the motor or turbos go on me and likely it's time for a new car and I never needed to worry about the leaks. Otherwise, should they ever become a major leak...the car will sensor a pressure issue and let me know and depending on what mileage I'm at, I can decide if it's worth fixing at that time or finally laying her to rest, rebuild or upgrade. There doesn't seem to be harm or a wear and tear worry in either sense. Personally, I have decided to fix the oil cooler and front cams and let these continue as is for the time being. I sense no lack of power, pressure or issues with the car and trust the experience I have spoken with. Regarding the upper pan and main rear seal, they also require dropping the assembly, disturbing suspension that can cause further issues and large costs, so the experts also said it's actually faster to pull the whole motor. It sounds extreme but there is a lot of labor that overlaps for these two areas, and like clockwork, an expert can yank the motor and save you about 6 hours of labor between both jobs doing it all at once, freedom of movement, etc. While you're in there, the only thing they advise is doing the motor mounts. Cheap enough and over time these can be subject to rattle. I think they're like $150 a piece or so...either way worth doing while you're in there because you'll be good into high mileage from there.

• Oil Cooler - This can be a little tricky to get to. A shop can do it for about $1-1.5k. Not the cheapest but not crazy either. You have a main feed line, the cooler and a return line. If you think with covers off that you can get in there yourself, you can do this job yourself but it's cheap enough that I may let the dealer do it. Not worth it to me to find the EXACT location leaking because if it's only the main line....how long before the return line or cooler itself has another seal issue? It's cost is cheap enough I'd rather do it all and ensure she's good to go! I'm still evaluating this job but currently am planning to do it myself if I can reach everything and can obtain all the tools I need access wise.

• Front Cam Seal Leaks - Again, precision and lubricants due to thermal cycle throughout life cycle ALWAYS see these fail. Very common and an easy fix. You have to uninstall the engine air filters on top of the motor, remove intakes, sensors and architecture in front of motor. It's also highly advised you buy a torque wrench, OEM bolts which are color coded representing torque values for motor seals to be proper (if you open the hood, you'll see the sensors mounted on the cam seal covers left and right side, look like oval or octagon style caps with turquoise or blue torque bolts around them, that is what you're freeing architecture up to get to). The dealership wanted $1.2k to do this job. I bought the seal kit, rings and lubricant OEM for $228 at the dealership and did this job on a Sunday afternoon at home. Easy enough to do and recommend a thousand dollar savings. This is very manageable on your own and the most important seal to do as it's usually the worst leaker you'll see and leaks towards alternator and other electronics, so best to keep in good straits.

Overall, I learned these leaks and seals are a fact of life with performance motors, precision seals only using lubricant's. Some people swear higher end, Ford sturdy and other lubricants fair better long term but remember that Mercedes designed these with thermal expansion in mind for the motor and everything involved, so I stick to OEM and don't violate specification. Engineered as intended...I stick to that. I'm driving no issue with the rear seal and upper pan issue. They're very minor and likely never become major...if they do, I will evaluate at that time for the given mileage whether she is worth saving. I think personally that anything below 150K miles is worth saving given the life of motor and turbos (expectation wise anyway) and I love the car. You do have to separate sentimental value with reality certainly...do what is right for you finance wise, affordability, paid off or not, etc. Anyway, hope this helps and if you have any specific questions about the jobs, tools or whatever, feel free to ask. Youtube of course has quite a few videos on the cam seals that are worth a go. Same with spark plug outlets, etc.

Best of luck and let me know what you decide

 

Hi Everyone - I too had multiple oil leaks on my 2012 CLS550 only 62K miles. My independent mechanic was able to repair many of them last November and noticed that I started having the wire harness issue with oil moving up by the ECU. He was able to clean it out fairly well, but over the summer, my car started misfiring and shaking like a Harley. I brought it in multiple times. first was to replace the ECU due to oil finally reaching it. after replacement, the car just kept sending check engine lights every 2 weeks. After a large repair bill, I decided sell it as I could not feel like I could trust that the car would not continue to find ways to extract more money from my wallet.

I wanted to keep this car forever considering its looks and performance plus the fact that it is a rare model at least where I am, but the harsh reality of maintenance / repair costs pushed my out.

 

Very nice, I sent it back and exchanged for another 2014 CLS 4matic with only 44k had it checked out and its all good, so this one is a keeper and I love it and see why others do as well.

 

That's a lot of leaking. I have a 2013 E63 Wagon (22k miles) and a 2014 CLS 550 (42k miles) black/black. My only CLS leaks were into the wiring harness and oil filter housing (minimal). Dealer repaired all. Let me know if you're looking to upgrade into a lower mileage CLS (California). tritonballplayer10@icloud.com

 

In most cases I just lettem leak. If it drips on the ground I'd just put an oil mat(s) in the skid plate under the engine, you just have to be wary about air flow because a lot of the cooling air passes that way. Considering the $ to fix vs a mat, seems obvious to me.
Then there's that oily alternator. They say that kills the alt but my guess is it only kills the removable module on the back side, which I believe you can swap out in the car. The oil and grime can also insulate/reduce cooling, and on an alt that's already making a lotta juice and not getting good cooling in the first place, I think it needs to be cleaned. I'd just douche it out with engine cleaner foam and carb cleaner.
Mine has a leak that's dripping on the ex manifold. Buggin the crap outta me because of the smell...

jct; I would've loved to try an experiment on your car to fix that oily ecu issue. I have what I believe is the fix, but my car doesn't leak enough to truly test it. Your saturated mess would've been perfect.

 

I had a leak addressed recently on my 2014 CLS550. It was the left rear cam plug. These are a $5 plastic part that has a rubber o-ring around it and they dry out and leak. The only reason I knew about it was it was dripping onto the manifold and I got the smell of burning oil. $140 repair at an independent shop that I 'sorta' trust.
I am also leaking from the lower oil pan.
This does not have a gasket per se. It's sealed with RTV silicone they just squirt on the union of the two like caulk. Nonetheless, $1K repair that I'll probably do down the road. More of a seep than a leak.

The camshaft solenoid magnets leaking are a known issue with this M278 engine too. There is a kit at places like FCP Euro with a sacrificial wiring harness https://www.fcpeuro.com/products/mer...-2761560790kt1

I am told this is a DIY project, but have only watched one video that was very vague in instructions. The shop I go to says they check these magnets and wiring every time someone comes in for a A service and if they see the wiring has oil seeping inside the connectors they replace for about $800. If this gets bad, I am told it can kill your ECU and then you are talking costly repairs.

I agree with some of the other comments. Engines will leak. Obviously if it is something that will lead to bigger problems you should address them. Otherwise, unless I am adding oil frequently, I let it go. Oil is cheap, MB shops are not.