PeachParts Mercedes-Benz Forum - Wet Carbon Deposits

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Wet Carbon Deposits

General Question:

What will cause black 'mushy/wet ' carbon deposits on all 6 cylinders of an m104 engine? No Smoke from the engine.....

Thanks,

Quote:

Originally Posted by latief (Post 2439897)

General Question:

What will cause black 'mushy/wet ' carbon deposits on all 6 cylinders of an m104 engine? No Smoke from the engine.....

Thanks,

Is the engine apart?

Did you do a compression and leak down test ?

Are the "deposits" on the cylinder wall..? (unlikely as the scraper ring should clean the cylinder )

Does it smell like oil or more like a light aromatic as gasoline?

I am trying to reverse engineer a problem with my car.,,

I did the head-gasket a couple of months ago. head was checked for leaks and straightness, but all was good....

I remembered yesterday that when i did this, my piston tops were covered with wet carbon. i literally cleaned them to a shine by wiping them with a rag.....

exhaust smells.... yes, but not sure how to describe it. most strong on first start.... their is very minimal oil consumption if any....

so generally speaking, what will would have caused this at the time?

Quote:

Originally Posted by latief (Post 2439916)

Ahhh..

Piston tops...

Probably a carbon build up caused by an inefficient fuel delivery system.
Best to set your AFR ratio to factory spec.

If you were to pull all six spark plugs would they also be black/wet..
Should be a light dry tan color if AFR is correct.

Run a tier 1 gasoline or ethanol blend..whatever is available in your area..
The additives in the higher octanes should keep your injectors, valves and piston heads clean.

You can also use Chevron Techron added to the gas tank..
The Tier 1 gas contains a Techron or equal additive.
Adding to the tank hastens the "clean up' process.

If compression and leakdown is to spec, then probably an overly rich AFR...your spark plugs are the best indicator ;)

I'd take it out and run it for an hour on an interstate....you know, let the thing really heat up and seat and stuff...just a thought

Quote:

Originally Posted by latief (Post 2439916)

Interesting, usually piston tops are caked with carbon, not wet.....and it requires some pretty serious chemicals to get those piston tops clean. I have no idea.

Sound like your kittens are clogged,or to much blow by from smog devices.

Quote:

Originally Posted by oldsinner111 (Post 2440406)

Sound like your kittens are clogged,or to much blow by from smog devices.

Thanks,

Actually, when i changed the headgasket. the egr tube was completely clogged that i had to replace it...it will not get clean ....I assume that is what you mean by smog devices?