Good afternoon,
I am growing increasingly concerned with the attached document, as my engine falls into this category. I noticed that this happens to GL's more then any other model for some reason, perhaps the weight? I was just wondering how many have you have had issues with M278 bi turbo and if you have any issues with valves/recalls or dealer replacement engines? Thanks!

Warning:
Validity Models with M278 engine and after the engine number
2789xx 30 128000

Engine no.:
278922 30 226353

 

I have not heard of any major issues with this platform, yet. I was talking to a Mercedes Dealership mechanic, who owns his own shop and good friend of a friend, said that he has not seen anything major come up with M278; just a hit or miss.

That PDF file said to replace the entire Left Bank Cylinder Head with all the internals? That sounds like rebuilding half the motor.

I did have the entire Bank 1 misfiring at a point, but it was due to a bad ignition coil connection and O2 sensor. It has been running perfectly ever since.

 

I have rebuild the engine m278 but it back together times it perfectly then but it in the car the engine start but with timing code , so I took the engine out and I bought another engine the one I bought is just for parts it's broken but it's complete so , I have done the timing on both engines the process is like so 1- crankshaft at the 40 degrees 2- checked the piston at tds or just after tdc as they call it 3- but the chains on the centre figure all on the mark , crankshaft mark on chain mark on the gear, centre figure mark on the chain mark on the gear, left bank chain as well with centre figure on mark, right chain too , tighten the centre figure now 4- but the chains on the camshafts matching the marking accordingly , the camshafts adjusters marking and the chains marking 5- deploy the timing chain tensioners 6- check the signal plates marking at the back the alignment is perfect with the heads , I even checked them with the tool to check them the little half circul tool to check the signal plates, and they all good but one didn't go with the tool even though the marking on it goes perfectly aligned with the head it was the right intake camshaft 6- now but back the head covers 7- rotate the engine to 53 degrees which is 17mm after the 40 degrees if you don't have them on the crankshaft wheel , so I but it to 53 degrees to check the timing through the holes of the timing sensors and the signal plates NOT SHOWING HALF ON THE HOLES I turned the engine again to 53 degrees just in case and no good tried over again and again no good So I did the timing again from the beginning and same thing no good timing I have no idea what to do and I if there is anything to do or to try I would do it just to get half plate on the sensor hole . If anyone have some advice please do