Lets not forget guys blocking the EGR is only half the job.
As its the oil vapour from the engine breather that make the soot turn to sludge.
I posted on this before the sever went down.
The engine breather pipe goes the crap oil trap at the back of the engine shown here
The pipe goes from the oil trap over the cam pulleys to where it joins the air intake in between the airfilter & turbo. So this is in effect unmeasured.
This allows oil vapour in to the turbo, the boost pipe, throttle flap and Inlet manifold that then turns the soot in to sludge.
So I removed the pipe as you can see, blanked off the open ended plastic cap & vented the engine breather pipe to under the front wheel arch from the metal pipe near the dip stick.