We bought our Chevy Venture (3.4) with 11 miles on the odometer. At 2,500 miles (first oil change) I switched it over to M1 5w30. The van now has 10,000 miles and I change the oil around 3-4000 miles because the oil has been getting dirty so quickly. I have around 3,000 miles on this oil and it isnt nearly as dirty as it usually is at this mile interval. I realize that I probably could have ran the synthetic longer but I cant stand to have black oil in my engines. The oil life monitor generally reads 70-80% when I change the oil. Was the reason for the dirty oil because of the engine breaking in? Did I switch to M1 too soon? What would you experts have done? Any input is appreciated.If I am a fool lay it on me. I can take constructive critisizm. Thanks.