i always change oil at 3000 to 3500 miles, i don't use the dic, my 03 truck's wouldn't tell you its time till after 5000, miles.

i just changed the oil in the regal after only 1500 miles and it was dirty already, all black and chit, and stinky. and i had lost a few quarts along the way with a oil pressure sensor leaking. so it already had 1/2 a change before the change.

so my guess is the last owners of this car didn't know what a oil change was.