iconoclast

I cannot find any straight-forward answers or information on the matter of carbon build-up. I have owned several FSI/GDI/DI engines and ALL needed carbon cleaning at one point or another despite Dealers claiming the issue does not exist and if it does show up it's from "poor US fuel & oil quality". This is my first MB w/ Direct Injection and I am curious to know if anyone on here has had any issues with carbon build-up or has completed cleanings on the M157.

At 29k Miles on a large engine like this I have to assume there is some sort of build-up just not sure if it is enough that warrants a cleaning or if it is completely choked like other engines in vehicles I own(ed).

Thanks.

iconoclast

I guess since there is no response it could go two ways... not an issue or no one on here opened up their engine to find out or do serious modifications.

Toadster

if you're really worried - spritz some water (use a spray bottle) into the intake while the engine is running, the carbon (if any) will solidify and burn up and go out the exhaust...

iconoclast

i assume a bg style cleaning could be done as well but i would love to see a photo of valves before anything is done. i guess i would be the first one to do this on this motor. let's see how this goes. if there is a cb i will have a manually cleaning done or a media blasting then take it from there. if there isn't anything i will say MB AMG Uber Alles and button it back up and go on with life.

2012 merc amg

Have not heard of any issues, but judging from all the carbon deposited around my chrome exhaust tips it must all be getting blown out of the engine in the exhaust.

iconoclast

i am not sure that is a fair way to assess... it may be similar to saying smokers shouldn't worry about their lungs since the smoke is being exhaled. there is still residue that remains inside despite having a bulk of it being expelled through through the exhaust.

2012 merc amg

I was kinda kidding when I said that. I really have not heard any complaints with the carbon which actually is surprising with how fat the fuel mixture is to support the kind of HP our cars put out. I guess they did something right with the design.

iconoclast

if MB escaped this through design or sheer accident the result is fine by me either way.

Zod

They don't , they sell a chemical solution you mix with your gas to remedy it.

Depends on your driving. So long as you go through the rev range (load) few times, it should be fine and helps clean it all out

also its different on force induction cars. from what i am told NA suffer more

but if you really want to know, i think they have a scope they use to look at your engine at the dealer..?

iconoclast

those fuel additives do not work since fuel does not wash over the valves since it is a direct injection engine. by design the fuel is injected directly into the chamber by-passing the valves. the italian tune-up method works on standard combustion engines that have been babied but on DI/FSI engines it simply bakes the gunk on further and solidifies it.

many manufacturers have redesigned their engines to be multiport direct injection where a supplemental injector is installed and a "wash cycle" is implemented into the programming of the injector spray and when the engine is under heavy load. this aids in mitigating build-up.

i have a great deal of experience with having carbon build up removed from Audi & BMW engines and the methods are very similar but i have not had an opportunity to do it on an MB engine.

my friend had an opportunity to break down an m157 engine but he has not made it to the valves yet. waiting on parts from germany:







there is substantial build-up on the piston crown but i am more concerned with IM & Valves or any area that may choke the engine and rob it of power.

KLR CLS

Interested in seeing this too. My s6 had big carbon issues and had to do cleaning every 30k or so to keep it from being choked. Carbon build up is generally less in fi applications but should be easy enough to see once the IM is pulled off.

2012 merc amg

Moral of the story, don't drive these cars like Grannies.

iconoclast

true, but on most DI engines this is a design flaw and inherent to the way it was designed to operate among differences in fuel in the NAR & PCV emissions requirements. this is not 100% user error or misuse. i am mainly concerned and curious about how these engines look after 20k+ miles...

Toadster

what's your removal process?

iconoclast

Now that we are further along in the life cycle of the motor and vehicle... Has any on here encountered Carbon Build-up on valves or PCV and coking of oil?

Manually scrubbing the valves and media blasting. Seafoam before and after then oil change. This has been the method completed on the vehicles I have own(ed).

ajs76

I'm a little surprised that it hasn't come up when guys have gotten their cars serviced (maybe too new?). I think the carbon cleaning was the most pushed service I've ever seen at my local BMW dealer.

dinman

i have a m156, so sort of off topic, but i'd love to see the inside of my engine since i have 136,000 miles

iconoclast

major issue on some of the bmw motors along with audi. i am guessing by the lack of discussion or concern it isn't an issue on these motors or at least not yet.

Mikeki7

My M157 has 90k miles and has been tuned for half of its life. Haven't had any engine issues, still pulls like a dream. I wonder what kind of carbon build up I might have, does not seem to affect engine operation.

christsay

Without a secondary set of injectors in the intake tract I can't imagine that the M157 is significantly more immune to carbon build than any other boosted DI motor.

Maybe when I'm done rebuilding the S14 in the M3 I'll tear down the intake of the wagon to see the intake valves...

-chris

iconoclast

I look forward to your findings.

christsay

heh, don't hold your breath. At the rate I'm going the M3 will be running in a couple of years...

https://s14net.vbulletin.net/forum/s...nd-scope-creep

-chris

jvakos

Reviving an old thread...

Iconoclast - did you ever open up your M157 and check the carbon build up if it was a possible issue? Am curious if carbon buildup is something M157 motors will be dealing with now that many are getting higher in mileage....

this is the only thread i've found anywhere on the topic of M157 motor and carbon build up in the intakes so maybe the M157 doesnt have the issue as bad as BMW motors where they get walnut blasted to remove the carbon ( )

curious if anyone has feedback on this (hopefully not which would mean no issues

iconoclast

The realist in me says ALL direct injection motors have this issue unless they have a supplemental injector with wash cycle. I have done cleanings on several other vehicles I own(ed) however I did not do it on either E63 because there wasn't enough data to convince me to go ahead with it. While that doesn't mean it does not have any build-up it means I could not justify the cost simply on a curiosity basis because there have been no signs of it, issues or cel indicating otherwise. If I had a base line dyno plot from day one and ran it today on the same dyno in the same setting then saw significant loss I would proceed however at this time the matter is inconclusive. For me.