PeachParts Mercedes-Benz Forum - View Single Post - Does soot in the intake find its way into the engine oil?

mach4 · #5 04-14-2014, 11:18 AM

I would say that the answer is logically and technically "yes", but the actual amount is probably unmeasurable.

Soot comes from combustion and over time finds it's way into the engine oil. With an EGR system, there is an amount of combustion gasses that are recirculated into the intake and become part of the mix of soot that are created by combustion. So combustion soot + EGR soot is the new base amount of soot that can find its way into the engine oil.

So the real question becomes, how much EGR gas is introduced. I couldn't find an actual answer but one source suggested that it could be up to 50% at idle. I find that a bit hard to believe, but who knows. At cruise it's probably in the low single digits...maybe less.

No matter what the amount, as said before, it's best to just be safe and just recirculate the EGR gasses to the exhaust where they belong and not the intake where they are guaranteed to muck up your intake, reduce mileage and decrease the efficiency of the engine.