Soot is normal, but loads of soft, fluffy stuff usually isn't. There is always a thin coating of dry soot in the prechambers. Wet, sticky, or oily deposits are not normal.

DO NOT use a wire brush!!!! You will likely damage the pintle (it sticks out of the nozzle) and if a wire breaks off, it can cause all sorts of internal damage to the cylinder.

Low compression, late injection (and valve) timing, and bad nozzles will result in carbon fouling. So will extended low speed, light throttle running. Excessive oil consumption will also cause carbon fouling, oily this time.

Do an "Italian tuneup" next chance you get.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!