Black Soot

DEF eliminates soot?

It is truly scary how many have no clue how these systems operate.

 

I have “White”(ash) soot all over my tips.

 

I have very rudimentary knowledge of emission systems, but I'm fairly certain DPF is for soot, DEF/SCR for nox, and EGR just to make shops money!

 

Hope this works, I remember entire sides of trailers black with soot, like the ICX truck or the orange R190 or the "Dual" truck, that I think is an Autocar. The Mack R model I drove was particularly smokey in between shifts. Blew a cloud, it did. I remember they had a device called the "puffilator", and was supposed to "eliminate the puff" of smoke. Old Detroits you could see them a coming a mile away. In fact, the reason for "up pipes" was to blow the soot over the cars. Check this out:
Vintage Trucks: A Colorful Gallery Of Old Diesel Semi-Trucks And Their Exhaust Stacks - Starting With The Smallest Muffler Ever - Curbside Classic