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1996 Jaguar XJ12, 2015 Land Rover LR4 HSE Lux, 2015 MB S 550 4MATIC Coupe, 2022 BMW X5 PHEV
Is the early *M278* that bad?
While I am looking at a “C216” CL-Class and have posted this in that forum, I am cross-posting this here because it and the “W221” are mechanically identical. I want to get as many opinions as possible.
I’ve been doing a lot of research on these, and would love a CL 550 4MATIC to replace my 2013 A8 L with the 4.0T. I’ve always loved the C216 design. Now then, the question is pre-facelift or post. I understand the M273 engine (5.5-liter) to be essentially bulletproof, outside of the early run. And I realize the M278 (4.7-liter) in the facelift models isn’t quite as solid.
But is it *that* bad?
I know it’s not as ruinously expensive as the competing early BMW N63 V8–which I’d categorically consider to be A Bad Engine; I’m just not sure how bad it is, and what I can expect. Opinions seem to range from “It’s great!” to “Run, Forrest, run!” And while I’m not averse to an expensive-to-own car, I don’t want one that’s going to have guaranteed problems.
All else equal, I’d love to have a post-facelift model. They’re easier to find with lower miles, without excess wear, and with the options I require (Keyless GO, Distronic Plus, Sport Package).
I'd love to know the truth, as a more recent M157 owner. But here is what I do know. The M278 is a drastically more complicated and less durable engine than the M273. It is unclear exactly what the statistics are (and that is key to calculating probability/risk), but I think it is pretty clear that the M278 has more expensive problems on a more frequent basis, and more than one can cause total engine destruction necessitating complete replacement. Again, it isn't clear what the actual statistics are, but I would say a big factor needs to be how much you actually prefer the M278 for the additional performance and fuel economy. If you could go either way, I'd RUN from an early M278 and some will say, run from all of them. I think there are a LOT of M278 vehicles on the road and I do not believe that every single one has required a new engine.
Another perspective that I cannot provide is, where does the M278 stack up in the range of German twin turbo V8s? I'd like to say (but have zero data) that I'd trust the M278 over the equivalent Audi or BMW offering but that isn't saying much, right?
Here's my take. There are a wide spectrum of vehicles that these motors were installed in which includes everything from near 3-ton SUVs to much lighter sedans and coupes. Then we factor in how the vehicles are driven and we have boat-towing lead foot boy racers to Palm Beach "idle to the club and back" owners and everything in between. Now also add the maintenance factor and how often these motors are seeing oil changes and it's clear (to me at least) that this is not a cut and dried discussion.
I just purchased a 48k S63 with the M157 and my buddy grabbed a 24k mile CLS550 with the M278 and - for us - we're not that worried. Both cars had impeccable maint histories, we're responsible adult owners and because these are not daily drivers for us (3k/yr max) it will be decades before either car even hits 100k. We're both nuts about maintenance too so the cars will see 3k annual oil changes.
No these motors are not Lexus V8s (got 2 of those myself) and they are not going to go 200k before anyone turns a wrench on them. But we don't need them to be and I'd bet quite a few folks here fall into the same camp as us. For older owners who just want a fun weekend/third car these motors will live a very long and useful life without much drama. And that's even with the occasional "good bye Mustang" blast :-).
However if you're the boat-towing GL550 owner with a Stage 1 tune whose wife dailys the car and puts 20k a year on it....maybe trading before 80k is a smart move :-)
1996 Jaguar XJ12, 2015 Land Rover LR4 HSE Lux, 2015 MB S 550 4MATIC Coupe, 2022 BMW X5 PHEV
Originally Posted by TripleDown
Here's my take. There are a wide spectrum of vehicles that these motors were installed in which includes everything from near 3-ton SUVs to much lighter sedans and coupes. Then we factor in how the vehicles are driven and we have boat-towing lead foot boy racers to Palm Beach "idle to the club and back" owners and everything in between. Now also add the maintenance factor and how often these motors are seeing oil changes and it's clear (to me at least) that this is not a cut and dried discussion.
I just purchased a 48k S63 with the M157 and my buddy grabbed a 24k mile CLS550 with the M278 and - for us - we're not that worried. Both cars had impeccable maint histories, we're responsible adult owners and because these are not daily drivers for us (3k/yr max) it will be decades before either car even hits 100k. We're both nuts about maintenance too so the cars will see 3k annual oil changes.
No these motors are not Lexus V8s (got 2 of those myself) and they are not going to go 200k before anyone turns a wrench on them. But we don't need them to be and I'd bet quite a few folks here fall into the same camp as us. For older owners who just want a fun weekend/third car these motors will live a very long and useful life without much drama. And that's even with the occasional "good bye Mustang" blast :-).
However if you're the boat-towing GL550 owner with a Stage 1 tune whose wife dailys the car and puts 20k a year on it....maybe trading before 80k is a smart move :-)
That's fair. For me, this would be a daily-driver, so between 18,000 and 25,000 miles of range annually.
I'm also considering the AMG CL 63 with the M157, though I hate that the airbag on the AMG S/CL 63 isn't leather-covered, and would swap that out.
Thankfully, the CLs seem to be among the most babied of the M157, M273 OR M278 cars; they don't generally attract hooligans. If it were an AMG C 63, or, indeed, a workhorse GL 550, I'd be a lot more wary.
Last edited by eurocarfanatic; Sep 13, 2023 at 06:48 PM.
Just thought I’d chime in because I see you’re interested in the very car I’ve owned for almost 10 years. I’ve had a 2010 CL550 4Matic for the last 9+ years and I still love it. it was purchased with around 11000 miles in early 2014..I’m now at 173000!!!
I’d strongly recommend getting a cl of this year as they went to the newer engines in 2011, 2010 was the last year the m273 was put in CL’s. I’ve documented every repair this car has needed on this forum so browse my post history to see what issues I’ve had..nothing major other than the intermediate axle shaft bearing, as that was the only repair I wasn’t able to do without a lift
Last edited by COUPCONNOISSEUR; Sep 14, 2023 at 09:29 AM.
1996 Jaguar XJ12, 2015 Land Rover LR4 HSE Lux, 2015 MB S 550 4MATIC Coupe, 2022 BMW X5 PHEV
Originally Posted by COUPCONNOISSEUR
Just thought I’d chime in because I see you’re interested in the very car I’ve owned for almost 10 years. I’ve had a 2010 CL550 4Matic for the last 9+ years and I still love it. it was purchased with around 11000 miles in early 2014..I’m now at 173000!!!
I’d strongly recommend getting a cl of this year as they went to the newer engines in 2011, 2010 was the last year the m273 was put in CL’s. I’ve documented every repair this car has needed on this forum so browse my post history to see what issues I’ve had..nothing major other than the intermediate axle shaft bearing, as that was the only repair I wasn’t able to do without a lift
Good info. Unfortunately, I didn't get the option to purchase a 2010 when they were newer (was barely out of high-school at that age!). Truth be told, I'd rather have a 2007-2010 (particularly a 2010, because it got the updated mirrors), but am having a hard time finding one with the options I want. I simply must have:
Distronic Plus
Keyless GO
4MATIC
Sport Package
I'll probably wait around until the right one comes up. I'll definitely take a look at your maintenance documentation, though. Ideally, this would be something I could avoid making $6,000+ repairs on. My 1996 Jaguar XJ12 just required a new transmission, and that was very expensive, despite it being essentially a GM 4L80E.
The M278 risk (along with most automotive risks) can be controlled to an extent. Aside from the advice about maintenance history (and your potential plan to be proactive), simply buying a less worn out car and keeping it a shorter amount of time probably does the most to limit risk exposure. Also, not driving it 15k/year (but letting them sit is bad, too....).
1996 Jaguar XJ12, 2015 Land Rover LR4 HSE Lux, 2015 MB S 550 4MATIC Coupe, 2022 BMW X5 PHEV
Originally Posted by kevm14
The M278 risk (along with most automotive risks) can be controlled to an extent. Aside from the advice about maintenance history (and your potential plan to be proactive), simply buying a less worn out car and keeping it a shorter amount of time probably does the most to limit risk exposure. Also, not driving it 15k/year (but letting them sit is bad, too....).
That sounds a lot like "maybe don't buy one" to me.
M278 is unmatched in it's class. It moves the 5500lb W221 past stangs, Camaros, vettes, Z's, etc. without complaining. And it's seriously factory de-tuned. Downpipes and a hand-held tuner and you're in the 600hp, 800ft/lb range. Pretty wild.
Every engine has some weak points if you like , but later M278s seem to remedy some leaks . M278 is my favorite engine and being a bi turbo modifying them renders uber cool performance stats as well
What exactly are the main issues with pre-face M278's? From what I've seen it's mainly cylinder scoring in cold climates, oil leaking into the wiring harness, & timing chain guides (though I was told the tensioners were fixed in 13'). My brother is looking at a (temporary daily) 13' S550 with a perfect dealer service history & 60,000 miles. He's searching for a mint W221 S350D but needs a daily at the moment.
My S550 has an early M278 with the OLD chain and the OLD Silitec Cylinder Lining....i am currently at 139k and the only thing Engine related i had to fix was a Camshaft adjuster and of course the leaking Camshaft Sensors (didnt have a leaking Camshaft Magnet yet though). The Engine has also been tuned for the last 20k or so and i do NOT take it easy on my car .
Last time i looked at my Cylinder Linings (about 10k ago) i did not find anything that i am concerned about. I believe a lot of the damaged stories come from people that run regular gas or crappy oil or 15k between oil changes etc. At that point i am not surprised you get issues. After the bad Camshaft adjuster i changed my Oil changes to 7 ish k miles. My chain is not stretched and the engine runs fine.
So in my opinion the Engine is great AS LONG as you take care of it. It IS a high performance engine and needs to be treated as such. Cheap out on maintenance and it will bite you in the A$$.
My S550 has an early M278 with the OLD chain and the OLD Silitec Cylinder Lining....i am currently at 139k and the only thing Engine related i had to fix was a Camshaft adjuster and of course the leaking Camshaft Sensors (didnt have a leaking Camshaft Magnet yet though). The Engine has also been tuned for the last 20k or so and i do NOT take it easy on my car .
Last time i looked at my Cylinder Linings (about 10k ago) i did not find anything that i am concerned about. I believe a lot of the damaged stories come from people that run regular gas or crappy oil or 15k between oil changes etc. At that point i am not surprised you get issues. After the bad Camshaft adjuster i changed my Oil changes to 7 ish k miles. My chain is not stretched and the engine runs fine.
So in my opinion the Engine is great AS LONG as you take care of it. It IS a high performance engine and needs to be treated as such. Cheap out on maintenance and it will bite you in the A$$.
Good luck in finding the Car you like !!
Thank you for your quick response. My brother and I change our oil every 5-7k miles (Depending on how hot florida decides to be lol). I had forgotten about the cam adjusters but that's not a big deal. Porsches have a big issue with cylinder scoring, but from what I've read, it only seems to be an issue in cold climates where cars are driven short distances. Perhaps this applies to the M278 as well?
I'll find some additional ones. Again, the big question is how often do bad things happen and how preventable are they. Hopefully the answer is "not too often" and "have an active maintenance program."
I'll save y'all the trouble - the Wizard found no issues with the motor in that video. His underling (former Benz tech) trotted out the usual talking points like cylinder scoring, leaky sensors on the front of the block, etc.
Only Mercedes themselves have the data to tell us how many of these motors have each problem and certainly some of them do.
I'll save y'all the trouble - the Wizard found no issues with the motor in that video. His underling (former Benz tech) trotted out the usual talking points like cylinder scoring, leaky sensors on the front of the block, etc.
Only Mercedes themselves have the data to tell us how many of these motors have each problem and certainly some of them do.
Yes I agree. Trying to walk the line between being informed and just spreading FUD.
Generally the 2014 model year is considered the "new" M278/M157, largely for the timing system update. However, I understand there were some additional improvements that would come after this, like that infamous timing cover coolant seal. And different cylinder coating. I guess those are kind of major...
I have a S500 4M with the M278 engine, odometer reading ≈ 396.*** km, no issues. Compression test all above 15 bar. Oile usage 0.8L/1500 km., mostly highway. Turbo's was changed at 380.000 km., no major slip, but the MB adviced the change. Gearbox flawless shift as the day I picked up the car from new.
I'm at the same mileage on my M278 in a '13 GL450. How did you know the cam adjuster was failing? Was it a noise, code, or performance?
Mine has not had the updated tensioner and check valves; however it does not rattle much at startup. I have started noticing a rattle when I left off gas when revving in park (coming down from 2500rpm ish. Thinking its tensioner related and not turbo wastegate.
I also a knock that goes away after warming up. It sounds like its coming from top of engine - wondering if this is cam adjuster.
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