dwlovell

So I have been through the carbon buildup adventure on my 335i and finding out this is a standard problem on almost all direct injection cars, particularly German brands.


It looks like VW and other have come up with a "dual injection" that has an extra set of injectors to clean the direct injectors where the fouling occurs.


Does anyone know if the "3rd generation direct injection" advertised on the GLA has engineering to prevent this carbon buildup?

rbrylaw

Sorry, I don't have a clue. Given Mercedes has been making direct injection engines for several years now, one would hope the 3rd generation engine in the GLA would not have any carbon buildup issues. But then I too had a BMW 335i and drove it for 4 years and I never had any issues with it.

This GLA forum isn't widely responded to. To me it says those who have the GLA are happily driving them without issue.

I hope someone who knows about the new direct injection can chime in.

dwlovell

Thanks for the reply. I am on my 5th year with 335i and that is when it hit for me. IT isn't a crippling problem, just incurs a 1000$ish carbon clean bill or else you lose power and have rough idle/start.

There is a huge thread on the C-class forum here about this issue and I guess that GLA uses the same engine as the C-Class. I guess maybe posting there might yield more responses. That thread has been quiet for a few years however.

https://mbworld.org/forums/c-class-w...n-buildup.html

I will try there.

doyall

Best I can tell the C Class got the M274 engine (longitudinal version of the M270 in the CLA/GLA) for MY14. May not be enough experience, at least in the USA, to conclude anything. Should be enough worldwide experience with this engine to determine if there is a problem but discovering the data could be difficult. I do know for a fact that the M270 in my GLA250 suffers from the familiar fuel dilution to the oil issue often associated with direct injection engines. See here: https://mbworld.org/forums/mercedes-...troubling.html MB obviously did not correct that situation in their DI engines. If my understanding is correct the fuel dilution problem contributes to the carbon buildup problem. The evaporates from the oil (fuel, water, lubricant, additives, etc.) flowing over the valves will build up over time because there is no fuel wash over the valves to clean them. Have heard some state that installing a catch can in the EGR(?) line could provide some benefit.

Let me say that I am disappointed MB would engineer and market a technology known to be fraught with problems without addressing them.

New DI Engines -- Excessive Carbon Buildup ?? was a good thread ... wish I had read it before my post!

rbrylaw

Yes, that thread link goes to engines that are not in the GLA or new C Class. If one applies logic here, Mercedes would likely make sure they do what they need in order to avoid significant warranty claims. It there's a not too costly means of avoiding this, it would save them significant money in the long run. They have a lot of bean counters pushing the engineers to design things they won't have to fix often.

None-the-less, I am getting both a new 2016 GLA250 and 2016 C300 and I'll be adding an extended warranty on both cars as I'm paying for them outright and don't want to face high maintenance costs over a 6 or 7 year period.

dwlovell

Understood. I only linked it because this is a problem that has plagued all implementations of Direct Injection and Mercedes is not unscathed. Other manufacturers have been modifying their designs to combat the problem. Was curious if anyone had heard about specific improvements. (Toyota, for example, has an extra set of injectors that still spray/wash the intakes purely for cleaning purposes.)


Anyway. I pulled the trigger on a GLA 250 and it will be here in about a week. I am pretty excited.

rbrylaw

Congratulations. Ours will be made the same week as the new C300 the 3rd decade of September (odd how they call weeks decades in the manufacturing process), with delivery by mid October. Please post plenty of pics of the new GLA when you get it, OK?!

dwlovell

Thank you. I do plan to take and post a bunch. I am a hobbyist photographer with semi-decent gear, so now I just have to think about a scenic location around Atlanta, GA to take the GLA for a photo shoot.

rbrylaw

Looking forward to seeing pics. I too am a hobbyist photo guy. Nikon D7100, with some nice glass.