Dave, I'm quite sure my oil cooler thermostat opened. Although I didn't touch it yesterday, I've touched it at other times after the same kind of driving and it was hot.

You guys might be right that there isn't a significant benefit to having the oil totally clear, especially if you use diesel-rated oil, but I do think there is at least a small benefit. The soot can't be good for anything, and as far as I'm concerned, it doesn't need to be there!

By the way, I have about 7000 miles on my car since I bought it and have done 6 oil changes, all of them with the flushing method I described, but only during the last one did I raise the rear and finally got rid of all the soot, though according to Larry that doesn't appear to be necessary and it appears all I needed to do was avoid driving the front onto ramps. Yes, I persisted until the soot was gone, and now I'm tired of doing oil changes on this car. Going back to 3000 mile intervals...

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL