I changed my oil this past weekend at 7K miles since last change (using Delvac). I was looking at the oil that had splashed on the side of the funnel I had used and saw a great deal of what i'll call soot that had gathered on the side of the funnel. This worries me because I went 7K miles - - - I wonder if I should consider an auxiliary filter. The 7K miles were mainly winter miles when dust is low, relative to the summer dust when I go fishing upcountry.

I had planned on switching to Mobil-1 at the next change, maybe I should have switched earlier, although I can't imagine that synthetic would change what I saw on the side of the funnel...

Bottom line: next oil change at 5K miles.

when i used to run dino oil in my truck it got dirty a lot sooner than now that i run synthetic. if your worried about the possible buildup of soot then you could definatly run a bypass filter system. if you run one of these systems you could extend your drain intervuls out to 25k+ miles. so it will save you money and wear and tear on your engine. just change your filters every so often, replace the lost oil, do an oil analysis and your good to go!