So our 2004 Volvo XC70 has been on full synthetic oil(German Castrol and Mobil 1 0w40)since 45,000 miles and it is now at 125,000 miles. Based on that I would think my engine is clean inside. I keep finding this black carbon like grit in my filters(Mann and Mahle). Is this anything to be concerned about or a possible problem? The first two pictures are the most recent oil change. It is a bit hard to see but you there is this crud built up on the bottom are of the filter. The 3 and 4th pictures are of an oil change a while back. Same stuff but seems to be more this time around: