Thank you for the public service announcement. I have been wary of this engine. One of the reasons being my indy telling me about a 2014 S550 that the valve seat had dropped on. How much of this technology is shared with the twin turbo V6?

 

I watched this prior to buying my S550 and while good information, I do think certain things are over-charactarized as "common" or "frequent".

Early cars, sure. but the 278 engines have been largely very reliable. In searching for my car, I came across tons of S, CLS, and E models with the 278 that were well over 100k some approaching 150k or more. They're maintenance queens, and they have some things that need to be addressed in higher mileage, but no worse than most other makes especially newer cars to be honest.

From what I recall, MB engines share quite a bit between 6 and 8 cyl counterparts. the 278 and 276 are likely very similar although I could be wrong. A valve seat dropping on a 278 is not something that I would think is a common failure point.

Nevermind the kinds of issues that other MFGs experience....Audi especially with their more recent hot v engines, some of the bmw 8 cylinders.

 

M278 engines are reliable except for valve guides, timing chains, turbo cooling hoses, oil in the wiring harness and bore scoring.

 

LOL....

 

Well, that sums it up I guess.

 

I like it , I can't imagine what you would say if had said M278 engines were unreliable lol

 

You know the only thing that really bothered me was the valve seats and that cover gasket that could cause mixing of the oil and coolent which he said was on the early M278's. The rest are manageable. Also he made no mention of bore scoring.

 

The video was released on 7/2022. The M278 had been out for 12 years. He says the cylinder heads are a big problem on these engines but he’s only replaced 2 at the shop. I’m sure many customers have turned the repair down and sold the car, but 2 repairs in 12 years and that’s “common”??

 

I know of one done by my indy. He is generally a politically correct kind of guy but was not that day.

 

Avoid talking yourself into something. Read this site thoroughly for M278 and M157 maladies. If you buy one of these things, set aside a pile of cash that will be deployed into the vehicle.

 

As I’m sure you know, problems are largely overblown on any forum. That is true for all makes / models. When I had my E63 there were lots of horror stories about the M156. In 72k miles that engine gave me zero problems.

I do understand that a large volume of cash would be needed for ANY late-model MB performance engine. That’s a given. Early M278s (particularly in the GL) seemed to have some issues but the 2014+ do not seem to be a problematic engine. Just my experience as an owner who has perused these forums for years.

 

This guy doesn’t even own a M278/M157 vehicle or a W222. It’s amusing and comical to see a NON OWNER talk about “reliability” based on research they’ve done from a online forum and YouTube. LOL

The M156 engine has nothing in similar to the M278…..you probably meant M157. Again shows how clueless you are.

Every manufacture has issues. BMW/Audi/JLR. Across the board. Timing chains, injector issues, piston rings, rod bearings, defective y-pipes, oil screen issues, etc etc etc. The list is long and goes on and on. Not one make is immune to issues or problems.

 

Yep typo. M157. Thanks for catching. Edited.

Regarding ownership, are you of the belief that you have to be the owner of the garbage dump to know whether it stinks or not?