M278 engine , reliability and issues experienced?
Thread Starter
Member
Joined: Jan 2010
Posts: 248
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From: Sacramento
W221 2013 S550 Rwd, W221 2010 S550 Rwd
M278 engine , reliability and issues experienced?
Hello all! Im looking at a 2013 s550 with the popular m278 V8TT engine. Seems like this engine has had significant issues with valves seats, chain tensioners , check valves, oil in harness etc...and misc issues resulting in complete engine failure mainly on the GL Platform. Im assuming due to the weight and the motor working harder is another reason. How has this engine treated you all in the S class ? Any severe issues? Thank you in advance
Super Member
Joined: Aug 2017
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From: Scottsdale AZ
2015 SL550 & 2012 S550 4matic
I have limited knowledge relative to many others in this forum this opinion is based on owning this car with said engine. Rock solid high performance engine if maintenance done on schedule by MB. Otherwise the issuis you sighted might happen. In general, the w221 series in the years you post are solid. Get the history and go from there .good luck.
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Joined: Mar 2020
Posts: 88
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2013 W221 S550 2016 C217 S550
2013 S550 4matic owner here. 100k miles. Third owner. Dealership maintained until 85 k miles. I have been doing the maintenance myself since buying 2 years ago. Had to replace a vacuum pump. That's it so far. Doesn't burn oil. I did a fair bit of research comparing the BMW N63 to the M278. I bought an S550 specifically for the engine. Yea, sometimes you get a bad car. But, I found in general the Mercedes V8 to be superior to the BMW V8. Alot less complaints. Mercedes carried over the M278 into the W222. That says alot IMHO. Look for a later production 2013 S550 with full service records.
Last edited by red996; Jan 9, 2021 at 04:27 AM.
Thread Starter
Member
Joined: Jan 2010
Posts: 248
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From: Sacramento
W221 2013 S550 Rwd, W221 2010 S550 Rwd
Thank you MBCO and red996 for your feedback.
Red996 i agree with you 100% , had a 750li with the n63 in the family. Boy did it drive nice but what a shame that BMW had so many design failures and issues with it. This vehicle will be maintained personally by myself at home as i used to be in the repair and service industry. There are a lot of threads on the GL platform but not here or 222 about the engine.
Red996 i agree with you 100% , had a 750li with the n63 in the family. Boy did it drive nice but what a shame that BMW had so many design failures and issues with it. This vehicle will be maintained personally by myself at home as i used to be in the repair and service industry. There are a lot of threads on the GL platform but not here or 222 about the engine.
Last edited by s5benzo; Jan 9, 2021 at 11:35 AM.
Member
Joined: Mar 2020
Posts: 88
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2013 W221 S550 2016 C217 S550
I wouldn't write off all BMW V8's as junk. I have a F13 M6 with the S63 V8. Although S63 does seem to have rod bearing issues at higher mileage it been a pretty solid engine. So far. 19 k miles only so far.
Completley stock.
Completley stock.
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Joined: Jan 2011
Posts: 212
Likes: 70
2003 S55 (SOLD) , 2012 S550
I drive a 2012 S550 with the M278 and here is my take on this. My engine was built before Feb 2012 so it has the old chain tensioners and the old chain design. I had the chain rattle a few month back and did the new tensioners and check valves but it turned out that one of the camshaft adjusters was bad on top of it. i did that one as well and now the engine i running great again. I did however do a little research into why a adjuster would go bad at 110k with a well maintained engine and find that the oil return from the turbos are right above the adjusters which means they will get VERY hot oil when you drive "spirited". As a result i am now changing my oil every 5k instead of every 10k as i did before. I also recently did a tune on the engine and i think these engines are fantastic. While doing the adjuster and tensioners i looked at the turbos and could not find any play or wear which is also great news.
The oil in the harness will come from the cam sensors and when my first one started leaking at about 90k i just replaced all 4. They are not expensive and take 15 minutes to replace all 4.
There is also a possibility of oil coming from the adjuster magnets but i have had no issue yet and i am now at 118k. And those are not expensive as well and can be replaced in a few minutes.
So in conclusion....if you are looking at a 2013 you will have the new chain design and should not have any issues as long as the engine was maintained well.
And as long as you know about the weaknesses and keep an eye on them i do not believe you will have any issues in the future.
Good luck.
The oil in the harness will come from the cam sensors and when my first one started leaking at about 90k i just replaced all 4. They are not expensive and take 15 minutes to replace all 4.
There is also a possibility of oil coming from the adjuster magnets but i have had no issue yet and i am now at 118k. And those are not expensive as well and can be replaced in a few minutes.
So in conclusion....if you are looking at a 2013 you will have the new chain design and should not have any issues as long as the engine was maintained well.
And as long as you know about the weaknesses and keep an eye on them i do not believe you will have any issues in the future.
Good luck.
Thread Starter
Member
Joined: Jan 2010
Posts: 248
Likes: 15
From: Sacramento
W221 2013 S550 Rwd, W221 2010 S550 Rwd
I drive a 2012 S550 with the M278 and here is my take on this. My engine was built before Feb 2012 so it has the old chain tensioners and the old chain design. I had the chain rattle a few month back and did the new tensioners and check valves but it turned out that one of the camshaft adjusters was bad on top of it. i did that one as well and now the engine i running great again. I did however do a little research into why a adjuster would go bad at 110k with a well maintained engine and find that the oil return from the turbos are right above the adjusters which means they will get VERY hot oil when you drive "spirited". As a result i am now changing my oil every 5k instead of every 10k as i did before. I also recently did a tune on the engine and i think these engines are fantastic. While doing the adjuster and tensioners i looked at the turbos and could not find any play or wear which is also great news.
The oil in the harness will come from the cam sensors and when my first one started leaking at about 90k i just replaced all 4. They are not expensive and take 15 minutes to replace all 4.
There is also a possibility of oil coming from the adjuster magnets but i have had no issue yet and i am now at 118k. And those are not expensive as well and can be replaced in a few minutes.
So in conclusion....if you are looking at a 2013 you will have the new chain design and should not have any issues as long as the engine was maintained well.
And as long as you know about the weaknesses and keep an eye on them i do not believe you will have any issues in the future.
Good luck.
The oil in the harness will come from the cam sensors and when my first one started leaking at about 90k i just replaced all 4. They are not expensive and take 15 minutes to replace all 4.
There is also a possibility of oil coming from the adjuster magnets but i have had no issue yet and i am now at 118k. And those are not expensive as well and can be replaced in a few minutes.
So in conclusion....if you are looking at a 2013 you will have the new chain design and should not have any issues as long as the engine was maintained well.
And as long as you know about the weaknesses and keep an eye on them i do not believe you will have any issues in the future.
Good luck.
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Member
Joined: Mar 2021
Posts: 78
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From: Erie, CO
2016 GL550
Vacuum pump
Do you have to replace the whole unit or could you for example just replace the diaphragm?
Thanks!
Member
Joined: Mar 2020
Posts: 88
Likes: 43
2013 W221 S550 2016 C217 S550
The vacuum pump is very easy to replace. I tried rebuilding it and got another 6 months out of it. In the end the check valve at the top of the pump that feeds into the transducer failed and leaked oil into the turbo waste gate vacuum lines causing a low boost situation. I couldn't find a replacement check valve so replaced it. Finally. Lol.
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2013 W221 S550 2016 C217 S550
No I didn't have to replace any lines. I got a vacuum tester and put a vacuum on them. Just glad it wasn't the wastegate actuators that were done. That's an engine out AFAIK.
Newbie
Joined: Sep 2021
Posts: 6
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Cl500
Hello all! Im looking at a 2013 s550 with the popular m278 V8TT engine. Seems like this engine has had significant issues with valves seats, chain tensioners , check valves, oil in harness etc...and misc issues resulting in complete engine failure mainly on the GL Platform. Im assuming due to the weight and the motor working harder is another reason. How has this engine treated you all in the S class ? Any severe issues? Thank you in advance
Newbie
Joined: Nov 2022
Posts: 1
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Volvo s90
dont even think of buying these engine . The list of problem is endless. I have cl500 already 6 years . Every thung is ok except this engine and i searching the internt years. It seems there is defect in these engine . Start from water pipes to timming chaines cracked cylinders . With maximum care mostly the engine will not last more than 200k km . And expect peoblems even belom 40k km .
what year is your engine from?
Member
Joined: Jan 2011
Posts: 212
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2003 S55 (SOLD) , 2012 S550
Never seen an engine that was made in 2 different years....and i guess i should be REALLY happy with my 132k miles (212k kilometers).
Again...if you know about the weaknesses and stay on top of them these engines are great and have a lot of potential (mine is stage 1 and pulls very nicely)
If you buy the cheapest merc on craigslist then you will likely get a car that was never maintained the way its supposed to be and you are just asking for trouble. I see plenty of people putting regular in the car and running non synthetic oil in them. Just because someone DOES drive a merc does not mean he/she can AFFORD to drive a merc. Unfortunately a lot of people drive the euro lux cars more for the appearance of having money and not because they are great cars.
Again...if you know about the weaknesses and stay on top of them these engines are great and have a lot of potential (mine is stage 1 and pulls very nicely)
If you buy the cheapest merc on craigslist then you will likely get a car that was never maintained the way its supposed to be and you are just asking for trouble. I see plenty of people putting regular in the car and running non synthetic oil in them. Just because someone DOES drive a merc does not mean he/she can AFFORD to drive a merc. Unfortunately a lot of people drive the euro lux cars more for the appearance of having money and not because they are great cars.
Newbie
Joined: Sep 2021
Posts: 6
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Cl500
Never seen an engine that was made in 2 different years....and i guess i should be REALLY happy with my 132k miles (212k kilometers).
Again...if you know about the weaknesses and stay on top of them these engines are great and have a lot of potential (mine is stage 1 and pulls very nicely)
If you buy the cheapest merc on craigslist then you will likely get a car that was never maintained the way its supposed to be and you are just asking for trouble. I see plenty of people putting regular in the car and running non synthetic oil in them. Just because someone DOES drive a merc does not mean he/she can AFFORD to drive a merc. Unfortunately a lot of people drive the euro lux cars more for the appearance of having money and not because they are great cars.
Again...if you know about the weaknesses and stay on top of them these engines are great and have a lot of potential (mine is stage 1 and pulls very nicely)
If you buy the cheapest merc on craigslist then you will likely get a car that was never maintained the way its supposed to be and you are just asking for trouble. I see plenty of people putting regular in the car and running non synthetic oil in them. Just because someone DOES drive a merc does not mean he/she can AFFORD to drive a merc. Unfortunately a lot of people drive the euro lux cars more for the appearance of having money and not because they are great cars.
Junior Member
Joined: Apr 2022
Posts: 23
Likes: 26
S550 4matic
07-2012 S550 here, German car with full MB History. Tensioners swapped according to TSB, 80'km down in 10 years. Everything is spotless and no oil leaks whatsoever, even camshaft sensors look fine and thus the harness.
I for myself think of it like "no worries until the magic 200'km mark" and if everything should be fine beyond this, then okay. Nevertheless we will have 2035 until i reach this mileage in kilometers and if political factors progress as they do, you will either have a diamond of a car worth overhauling the engine or a world where billionaires will be the only ones left able to maintain or fuel the car.
I exactly got the car in mid 2021 to experience what it is until the world has turned fully anti-combustion so you should think about getting a decent one and make up your mind when to drive it. As a daily for getting your errands and groceries, no way at least here in Germany. I rather take it as a dream transport solution once a week when goind to the office and back, 120 miles including german Autobahn.
And if that dream should be over in 10 years than i am a blessed man.
Hope you can get what i am trying to say. Get a jetta if you need an everyday allrounder (i do like jettas, please get me right, an S550 is a rare privilege getting even more so as times are a changing).
I for myself think of it like "no worries until the magic 200'km mark" and if everything should be fine beyond this, then okay. Nevertheless we will have 2035 until i reach this mileage in kilometers and if political factors progress as they do, you will either have a diamond of a car worth overhauling the engine or a world where billionaires will be the only ones left able to maintain or fuel the car.
I exactly got the car in mid 2021 to experience what it is until the world has turned fully anti-combustion so you should think about getting a decent one and make up your mind when to drive it. As a daily for getting your errands and groceries, no way at least here in Germany. I rather take it as a dream transport solution once a week when goind to the office and back, 120 miles including german Autobahn.
And if that dream should be over in 10 years than i am a blessed man.
Hope you can get what i am trying to say. Get a jetta if you need an everyday allrounder (i do like jettas, please get me right, an S550 is a rare privilege getting even more so as times are a changing).
MBWorld Fanatic!
Joined: Aug 2021
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1983 Nissan Shltbox
I love my M278. I can keep it stock, and it blows cars away, or I can plug a Renntech tuner into it and in a few seconds go from Ridiculous speed to Ludicrous speed in a five thousand pound lounge.
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Joined: Oct 2017
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w210 E55
I’ve worked on a ton of 278/157 engines. 278 engines can have major issues. Especially in a 2012, cylinder scoring, just bad engines in general. But we also have a customer with an e550 that runs 11.0 in the 1/4 with 140k miles on his car. While yes they are badass engine and can make really good power. I would get a m273 car for sure. I just can’t trust a m278
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1987 Porsche 928 S4, 2009 Mercedes E350, 2011 Mercedes GL450, 2003 Mercedes ML350
I've heard both myths and facts about the cylinder scoring...
One possible myth is that m278s in colder climates are culprits for the scoring issue
I think the reality is multiple previous owners of these cars have just started them and left their driveways without a proper warmup.
It used to be in the 80s you would let a turbo car warm up for a minute or 2 before going. That seems to be dismissed these days. I think for the cylinder walls to receive proper lubrication, warmup is necessary. A cold start mixture on a turbo car can be very rich, washing oil off cylinder walls, resulting in....well cylinder wall scratches.
One possible myth is that m278s in colder climates are culprits for the scoring issue
I think the reality is multiple previous owners of these cars have just started them and left their driveways without a proper warmup.
It used to be in the 80s you would let a turbo car warm up for a minute or 2 before going. That seems to be dismissed these days. I think for the cylinder walls to receive proper lubrication, warmup is necessary. A cold start mixture on a turbo car can be very rich, washing oil off cylinder walls, resulting in....well cylinder wall scratches.
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S550 4matic
I see that an aux heater is not available from the factory outside the EU when i compare the user manuals. Interesting. It also has an implication on the clinate buttons as the OFF button is then both the OFF and residual heat "REST" button, the button right to that us then a two indicator (blue and red) one for the aux heater.
Red is for heating, blue is for venting which is also conducted automatically in hot summers after parking to dehumify the evaporator surface of the AC. For approx. 40mins...
Getting back on the cylinder issue, here in the Alps we or at least i am a sucker for parking heaters. Webasto retrofits are very common and they also manufacture the unit MB has installed from the factory. I pre heat all my cars before i drive them, even in summer (we only have really warm nights for a few weeks!). That way the engine is idling like a hot summer cold start even in winter as it is at least 50% of target temp when cranking, you can hear and feel the difference clearly.
In a nutshell, Mercedes has put some thought into helping the engine warm up when a parking/aux heater is present and the climate is cold and maybe they have had the fact in mind that otherwise a cold start and fat mixture could be consequential in a way, at least in scenarios where short drives are the case...
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From: Albuquerque
'10 CL550, '12 GL550
Pretty much standard practice for Mercedes is to perform a "facelift" during a model run. Usually 1/2 to 2/3 into the run. Typically facelifts are where new engines are introduced ... meaning the same engine is usually carried forward to the next model.
Of course not always ... W221 started with the new M273, which wasn't carried over from W220. But then, W221 was introduced at same time as the W211 (E-class) facelift, at which time E-class got the M272 and M273.
Of course not always ... W221 started with the new M273, which wasn't carried over from W220. But then, W221 was introduced at same time as the W211 (E-class) facelift, at which time E-class got the M272 and M273.
Last edited by lkchris; Nov 30, 2022 at 10:02 PM.
Junior Member
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S550 4matic
For example, the last 221s which already had the M278 (there are some facelift 221s with M273!) were equipped with the larger brakes and quad exhaust. Just like with Audi RS6/7s, two exhaust outlets on each side are visible when you look into the chrome cover and one on each side is operated by valve control. In Germany, it is allowed to open above 60kph, MB opens it under a certain level of throttle which is earlier in sportmode. No real loud noise, but definitely more rumble when you push it.
To me thats not important, but the larger brakes (which means 18 inch wheels are smallest) are of course a nice thing. All these details were taken to the frist w222 models in 2013.
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Posts: 200
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Class S 500 M278
I'm the happy owner of a S500 with the M278 engine. Very close to pass 400.000 km., no issues - full service by MB ofc. Turbo's changed at 375.000 km., and all 4 air struts. Lindemann additives added from new by all regular olie changes.
