MBRedux

Link: https://mbworld.org/forums/glk-class...99192-stp.html Read this....

Now this is my huge concern... My wife is talking about trading in the GLK for a C-Coupe but I am very worried about these new direct injected (DI) Merc engines. If they are anything like VAG's (Audi, VW Group) engines, they will suffer from severe carbon build-up on the intake valves after 50,000 miles. The reason is these DI engines eliminate the port fuel injectors and installs them directly inside the cylinder. So the intake valves are therefore no longer cleaned by detergent gasolines, only air mixed with crankcase gases and EGR gases. Over time these valves begin to carbonize as the oil vapor sticks and burns. In fact these new DI engines are suffering major carbon issues over on Audi forums since they introduced the technology about 6 years ago.

Has MB been able to overcome this major engineering problem on their new DI engines, or are we all going to start screaming in a few years as these problems start to become troublesome?

Germancar1

I would ask a Mercedes dealer mechanic about this, its a very good question with no real answer on the web.

I would think Mercedes has found a solution to this problem since they waited so long to embrace DI for the U.S. market.

There was an article somewhere about the solution for this.


M

MBRedux

Spoke with Mercedes tech line... they haven't a clue either but agree it can become a huge issue...

jctevere

I'm going to reach out to some connects at MBUSA, posted this comment so I will be subscribed, will keep you posted.

Breitling65

There is cons/pros in anything, direct injection is known as better than port port injection in most technical aspects. Most important to me that engine takes/sicks as much fuel as it needs per particular moment. Less gas is required and better output as results. I am not planning to drive this car beyond warranty period is over and even if I do I wouldn't worry much about Mercedes Benz engines, nothing better anyway exist

MDMercedesGuy

I've had some concerns with this as well. Not enough to prevent me from buying the car, mind you - but it was on my mind. DI is the way of the future, though - so someone will have to come up with an additive or such to help with this eventually I would think.

I'd also be curious to see what conditions the cars that are having the problems are being driven under. My vehicles tend to see the upper end of the rev range several times a week - there's something to be said for literally blowing the carbon out of an engine.

golfster

The Search Function shows a lot of posts with concern over the D.I. engine. The technology isn't new but the long term effect of US fuel on US bound M-B D.I. engines remains to be seen. Google Search links to many articles referencing the same concern.

Time will tell...

Woodstockz

In itself, direct injection does not create a great performance advantage, but it allows for greater compression or boost without pre-ignition. Carbon on the intake valves must be coming from camshaft overlap.

Subaru has an interesting solution, a combination of both port and direct injection.

MBRedux

Please refer to this thread: https://mbworld.org/forums/c-class-c...s-engines.html