Just as a result of an engine is available in a premium car from a widely known model does not imply there cannot be issues with the powerplant. As a living proof, I Do Cars tears aside the Mercedes-Benz M278 twin-turbo 4.7-liter V8 from an ML550 and finds extreme points contained in the cylinders.

Things do not begin off properly. Turning the engine reveals some bizarre clunking sounds that should not be current. Also, a number of the spark plugs present numerous deposits on them. The consumption ports current numerous carbon on the valves – much more than regular for a powerplant with a direct-injection gas system. Also, one of many timing chain tensioners is free, suggesting another person labored on this mill up to now.

As extra elements come off, it turns into clear that the oil on this engine is nasty. The filter is stuffed with tremendous items of metallic, hinting on the carnage to return. The issues reveal themselves as quickly because the cylinders come off. There are deep scores in a number of of the cylinders. Eric from I Do Cars notes these scrapes aren’t simply deep sufficient to really feel with a fingernail however to catch together with your hand. As you’d anticipate, the piston skirts additionally present numerous put on.

Mercedes used the M278 engine in varied fashions, together with some E-, S-, CL-, CLS-, ML-, and GL-Series choices. According to Eric, the problems with engine bore scoring are additionally current within the AMG variant of this powerplant that goes by the inner moniker M157. The M276 V6 is not immune from this drawback, both.

Unfortunately, Eric would not provide a trigger for the bore-scoring challenge. Folks on varied Mercedes-Benz-focused boards additionally report this drawback, however an actual motive is difficult to pinpoint. Some of us say there’s an excessive amount of time between recommended oil changes. Others declare it is an issue with the piston rings. Meanwhile, others are having no problems.