M278 issues
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 73
Likes: 6
From: Chicagoland
2013 C300 4Matic
M278 issues
Hello,
I tried searching this and the CLS forums for a thread which has all the M278 issues but i couldn't find one (or they were buried). I'm conducting research as I want to take on the monumental task of putting an M278 in my W204 4matic C300.
I've done a lot of digging and the thing that keeps coming up is the tensions on the earlier M278 models. I also came across another scary thread of an engine from GL which had to have its cylinders honed at 70k miles because of low compression due to what appears to be Silitec coating wear resulting in scratches. The engines I keep finding on the market are at the 60-70k mile range and as so i wanted as much input from people who have dealt with this engine as possible.
As a whole, what are your impressions of the M278?
How many miles do you have on yours and have you had any major issues?
I tried searching this and the CLS forums for a thread which has all the M278 issues but i couldn't find one (or they were buried). I'm conducting research as I want to take on the monumental task of putting an M278 in my W204 4matic C300.
I've done a lot of digging and the thing that keeps coming up is the tensions on the earlier M278 models. I also came across another scary thread of an engine from GL which had to have its cylinders honed at 70k miles because of low compression due to what appears to be Silitec coating wear resulting in scratches. The engines I keep finding on the market are at the 60-70k mile range and as so i wanted as much input from people who have dealt with this engine as possible.
As a whole, what are your impressions of the M278?
How many miles do you have on yours and have you had any major issues?
Senior Member
Joined: Apr 2017
Posts: 367
Likes: 34
14 polar white E550
These engine are really reliable for what they are . Things you need to watch for are the chains were updated in the later models I think 13 or 14 and up had the updated ones . Also the coolant lines for the turbos tend to leak from time to time . And last but not least the camshaft sensor suffer from oil getting into the harness .
Super Member
Joined: Nov 2011
Posts: 973
Likes: 376
From: Austin, TX
2013 SL550 BiTurbo
120k miles on car/engine. I've made 650hp, +750tq for the last 15k(550/650 for 10k before that) and I'm very close to the fuel system's limit, even using AMG in-tank pumps. been pretty reliable. I have a stock front driveshaft on the way now, but it's u-joint was damaged when I bought the car(put on aftermarket one last week and twisted it in half like it was a paper towel roll! smh).
I have a slight drip from front cam adjuster cover plates that I need to reseal and I'll be doing the turbo waterlines, replacing the I/C pump with a CWA100 and replacing the t-stat/housing soon, just for preventive measures. Keep up on the maintenance and it'll treat you right.
I have a slight drip from front cam adjuster cover plates that I need to reseal and I'll be doing the turbo waterlines, replacing the I/C pump with a CWA100 and replacing the t-stat/housing soon, just for preventive measures. Keep up on the maintenance and it'll treat you right.
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 73
Likes: 6
From: Chicagoland
2013 C300 4Matic
120k miles on car/engine. I've made 650hp, +750tq for the last 15k(550/650 for 10k before that) and I'm very close to the fuel system's limit, even using AMG in-tank pumps. been pretty reliable. I have a stock front driveshaft on the way now, but it's u-joint was damaged when I bought the car(put on aftermarket one last week and twisted it in half like it was a paper towel roll! smh).
I have a slight drip from front cam adjuster cover plates that I need to reseal and I'll be doing the turbo waterlines, replacing the I/C pump with a CWA100 and replacing the t-stat/housing soon, just for preventive measures. Keep up on the maintenance and it'll treat you right.
I have a slight drip from front cam adjuster cover plates that I need to reseal and I'll be doing the turbo waterlines, replacing the I/C pump with a CWA100 and replacing the t-stat/housing soon, just for preventive measures. Keep up on the maintenance and it'll treat you right.
s the drip from the cam adjuster something common?
Super Member
Joined: Nov 2011
Posts: 973
Likes: 376
From: Austin, TX
2013 SL550 BiTurbo
yeah, the o-rings on the adjusters are seeping as well as the plate that they are mounted to(it is sealed to the head with black sealant and uses one-time use screws that must be replaced as well).
I believe your C550 is going to run really well. I'll be following you to watch your progress on this. I'm running 11.3 @ 122 in the summer heat with high DA. With some stickier tires and cooler weather, looking to break into the 10's by EOY. Still on stock turbos
I believe your C550 is going to run really well. I'll be following you to watch your progress on this. I'm running 11.3 @ 122 in the summer heat with high DA. With some stickier tires and cooler weather, looking to break into the 10's by EOY. Still on stock turbos
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 73
Likes: 6
From: Chicagoland
2013 C300 4Matic
Looking at engines i also got an additional question. Besides an oil pan that accommodates for the front drift shaft to go through it, are RWD and AWD engines the same?
Where im going with this is, if i get a better deal on a RWD engine I'd rather do that and change the bottom part of it myself.
Where im going with this is, if i get a better deal on a RWD engine I'd rather do that and change the bottom part of it myself.
Super Member
Joined: Feb 2019
Posts: 681
Likes: 405
From: FL
2012 E550 sedan 2019 E63 Wagon
Looking at engines i also got an additional question. Besides an oil pan that accommodates for the front drift shaft to go through it, are RWD and AWD engines the same?
Where im going with this is, if i get a better deal on a RWD engine I'd rather do that and change the bottom part of it myself.
Where im going with this is, if i get a better deal on a RWD engine I'd rather do that and change the bottom part of it myself.
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MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,975
Likes: 1,343
From: Cincinnati
2010 E350 4Matic
What about the valve seat issues? https://mbworld.org/forums/gl-class-...re-solved.html
Last edited by MBNUT1; Sep 9, 2020 at 10:15 PM.
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Thread Starter
Junior Member
Joined: Feb 2016
Posts: 73
Likes: 6
From: Chicagoland
2013 C300 4Matic
MBWorld Fanatic!
Joined: Dec 2011
Posts: 1,273
Likes: 129
From: Orlando, FL
2015 GL550 4matic
I just bought a CPO 2015 GL550 and starting trolling x166 threads, scary that one thread with the engine tear downs. I've been more than happy with my E550 for 5 years and no problems other than the AC compressor dying last week. I have 1 year CPO warranty on the GL, might extend it if anything seems funny in the next year. I don't see that scary stuff on the W212 side.
Out Of Control!!
Joined: Sep 2018
Posts: 14,663
Likes: 4,567
From: unbegrenzt
2017 GLE350 4MATIC
https://mbworld.org/forums/gl-class-...78-engine.html
https://mbworld.org/forums/gl-class-...rebuild-2.html
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,975
Likes: 1,343
From: Cincinnati
2010 E350 4Matic
@m1l3n I haven't seen engine numbers or years mentioned on the site. Need to dig up all the relevant threads.
https://mbworld.org/forums/gl-class-...78-engine.html
https://mbworld.org/forums/gl-class-...rebuild-2.html
https://mbworld.org/forums/gl-class-...78-engine.html
https://mbworld.org/forums/gl-class-...rebuild-2.html
https://mbworld.org/forums/gl-class-...re-solved.html
Super Member
Joined: Nov 2011
Posts: 973
Likes: 376
From: Austin, TX
2013 SL550 BiTurbo
-Piston scuffing: I'm not aware of personally and have not looked into.
-Timing chain: Here is a quote from another thread about effected engines-
"M278 engines affected as follows:
Engine 278:
1) Up to engine number 278 9xx 30 073273 install check valves and chain tensioners
2) From engine number 278 9xx 30 073274 up to engine number 278 9xx 30 103675 (February 2013) install check
valves only (optimized tensioners installed in this production range)"
Here is a link to a post with the bulletin info:
https://mbworld.org/forums/5738609-post153.html
-Oil in harness from cam sensors: this is a sensor issue. There a 4 cam sensors, just pull the connector and check it for oil. If there is oil, clean thoroughly with brake cleaner and allow to dry(use compressed air if possible). Then clean it again. Replace the cam sensors that are leaking oil and you should be good to go. I had oil in my harness and it actually wicked down to the driver's O2 sensor connector. I replaced all my sensors early on when I bought it last year. I had an engine light for Left Front(precat) O2 sensor and car started running like poo. Found oil in the connector when I replaced the sensor. Cleaned it very well, let it set disconnected overnight, recleaned it the next day and put everything back together. I pulled the exhaust back out for some other work 2 months later and checked the connector and it was still dry. Some people have had to pull motor and replace their harness, lucky mine was not that bad.
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,975
Likes: 1,343
From: Cincinnati
2010 E350 4Matic
I guess it's a good thing that EV's are coming because Mercedes seems to be losing the recipe for successful ICE design.
Last edited by MBNUT1; Sep 11, 2020 at 02:00 PM.
